CAT 2020 Slot 1 DILR Question & Solution
Data Set
Question 1
Who among the following did not appear for the Mathematics examination?
Solution:
Based on Condition II, we understand that the student who missed the Mathematics examination did not miss any other examination. This indicates that the Maths score is bound to be the average of the best 3 out of the 4 exam scores obtained by this candidate. Based on this inference, we can proceed with identifying the math score that can be represented as an average of the rest of the scores. We can straightaway eliminate Deep and Esha as potential candidates, given that their Mathematics score is greater than the rest of the exam scores.
For Alva: best 3 out of 4 - 80(English), 75(Hindi), 75(Science)
Avg. = $230/3 = 76.67 e 70$
For Carl: best 3 out of 4 - 80(Hindi), 90(Social Science), 100(Science)
Avg. = 270/3 = 90 which matches the given value
$\therefore$ Carl most likely missed his Mathematics examination.
For Foni: best 3 out of 4 - 83(English), 83(Social Science), 88(Science)
Avg. = $254/3 = 84.67 e 78$
Hence, we observe that only Carl has missed his Mathematics examination. Hence, Option B is the correct answer.
Question 2
Which students did not appear for the English examination?
Solution:
Based on Condition II, we understand that the student who missed the Mathematics examination did not miss any other examination. This indicates that the Maths score is bound to be the average of the best 3 out of the 4 exam scores obtained by this candidate. Based on this inference, we can proceed with identifying the math score that can be represented as an average of the rest of the scores. We can straightaway eliminate Deep and Esha as potential candidates, given that their Mathematics score is greater than the rest of the exam scores. After estimating the average scores for the rest of the candidates, we observe that only Carl has missed his Mathematics examination.
For Carl: best 3 out of 4 - 80(Hindi), 90(Social Science), 100(Science)
Avg. = 270/3 = 90 which matches the given value
$\therefore$ Carl missed his Mathematics examination.
Further, based on Condition III, we can surmise that the student who missed Hindi and Science should have similar average scores in these two subjects. We notice that Alva has the same score of 75 in both Hindi and Science. The same can be said about Deep, who has a score of 90 in both these subjects. Thus, one out of Alva and Deep missed out on Hindi and Science examination, while the second individual missed out only on the Hindi examination.
Since we know that Carl, Alva and Deep are unlikely to have missed out on the English exam, we can divert our attention to determining which individual out of Bithi, Esha and Foni failed to appear for this subject. However, we notice that Bithi's English score is greater than the rest of her scores, thereby helping us eliminate her as the potential candidate.
For Esha: best 3 out of 4 - 85(Hindi), 95(Mathematics), 60(Science)
Avg. = 240/3 = 80 which matches the given value
$\therefore$ Esha most likely missed her English examination.
For Foni: best 3 out of 4 - 78(Mathematics), 83(Social Science), 88(Science)
Avg. = 249/3 = 83 which matches the given value
$\therefore$ Foni most likely missed her English examination.
Based on Condition I, we know that exactly two candidates missed the examinations for English, Hindi, Science, and Social Science.
For English, we determined these individuals to be Esha and Foni. For Hindi, we determined these individuals to be Alva and Deep. For Science, we know one of the individuals is either Alva or Deep. Given that Carl, Alva and Deep cannot be a part of the group that missed Science or Social Science exam, we can proceed by carefully scrutinizing the rest of the group that includes Bithi, Esha and Foni.
We notice that Bithi has a similar score in both Science and Social Science examination. Assuming that she did miss these exams, let us proceed to check if this was actually the case.
For Bithi: Best 2 out 3 - 90(English), 80(Hindi)
Avg = 170/2 = 85 which matches the given value
$\therefore$ Bithi is likely to have missed her Science and Social Science examinations.
We additionally notice that Foni has a similar score in English and Social Science. On considering the best 2 out of 3 scores, the average value of the score for both the subject holds (equal to 83). Thus, we can conclude that Bithi and Foni missed their Social Science examination.
Thus, the students who missed just one exam were: Carl (Mathematics); Esha (English) and one out of Alva and Deep (Hindi).
Hence of the six students, we can correctly determine the missed subjects for four of them (except Alva and Deep):
Mathematics: Carl ; English: Esha & Foni ; Hindi: Alva & Deep; Science: Bithi & one out of Alva and Deep ; Social Science: Foni & Bithi
Hence, the correct answer to this question is Option D: Esha and Foni.
Question 3
What BEST can be concluded about the students who did not appear for the Hindi examination?
Solution:
Based on Condition II, we understand that the student who missed the Mathematics examination did not miss any other examination. This indicates that the Maths score is bound to be the average of the best 3 out of the 4 exam scores obtained by this candidate. Based on this inference, we can proceed with identifying the math score that can be represented as an average of the rest of the scores. We can straightaway eliminate Deep and Esha as potential candidates, given that their Mathematics score is greater than the rest of the exam scores. After estimating the average scores for the rest of the candidates, we observe that only Carl has missed his Mathematics examination.
For Carl: best 3 out of 4 - 80(Hindi), 90(Social Science), 100(Science)
Avg. = 270/3 = 90 which matches the given value
$\therefore$ Carl missed his Mathematics examination.
Further, based on Condition III, we can surmise that the student who missed Hindi and Science should have similar average scores in these two subjects. We notice that Alva has the same score of 75 in both Hindi and Science. The same can be said about Deep, who has a score of 90 in both these subjects. Thus, one out of Alva and Deep missed out on Hindi and Science examination, while the second individual missed out only on the Hindi examination.
Since we know that Carl, Alva and Deep are unlikely to have missed out on the English exam, we can divert our attention to determining which individual out of Bithi, Esha and Foni failed to appear for this subject. However, we notice that Bithi's English score is greater than the rest of her scores, thereby helping us eliminate her as the potential candidate.
For Esha: best 3 out of 4 - 85(Hindi), 95(Mathematics), 60(Science)
Avg. = 240/3 = 80 which matches the given value
$\therefore$ Esha most likely missed her English examination.
For Foni: best 3 out of 4 - 78(Mathematics), 83(Social Science), 88(Science)
Avg. = 249/3 = 83 which matches the given value
$\therefore$ Foni most likely missed her English examination.
Based on Condition I, we know that exactly two candidates missed the examinations for English, Hindi, Science, and Social Science.
For English, we determined these individuals to be Esha and Foni. For Hindi, we determined these individuals to be Alva and Deep. For Science, we know one of the individuals is either Alva or Deep. Given that Carl, Alva and Deep cannot be a part of the group that missed Science or Social Science exam, we can proceed by carefully scrutinizing the rest of the group that includes Bithi, Esha and Foni.
We notice that Bithi has a similar score in both Science and Social Science examination. Assuming that she did miss these exams, let us proceed to check if this was actually the case.
For Bithi: Best 2 out 3 - 90(English), 80(Hindi)
Avg = 170/2 = 85 which matches the given value
$\therefore$ Bithi is likely to have missed her Science and Social Science examinations.
We additionally notice that Foni has a similar score in English and Social Science. On considering the best 2 out of 3 scores, the average value of the score for both the subject holds (equal to 83). Thus, we can conclude that Bithi and Foni missed their Social Science examination.
Thus, the students who missed just one exam were: Carl (Mathematics); Esha (English) and one out of Alva and Deep (Hindi).
Hence of the six students, we can correctly determine the missed subjects for four of them (except Alva and Deep):
Mathematics: Carl ; English: Esha & Foni ; Hindi: Alva & Deep; Science: Bithi & one out of Alva and Deep ; Social Science: Foni & Bithi
Hence, the correct answer to this question is Option B: Alva and Deep.
Question 4
What BEST can be concluded about the students who missed the Science examination?
Solution:
Based on Condition II, we understand that the student who missed the Mathematics examination did not miss any other examination. This indicates that the Maths score is bound to be the average of the best 3 out of the 4 exam scores obtained by this candidate. Based on this inference, we can proceed with identifying the math score that can be represented as an average of the rest of the scores. We can straightaway eliminate Deep and Esha as potential candidates, given that their Mathematics score is greater than the rest of the exam scores. After estimating the average scores for the rest of the candidates, we observe that only Carl has missed his Mathematics examination.
For Carl: best 3 out of 4 - 80(Hindi), 90(Social Science), 100(Science)
Avg. = 270/3 = 90 which matches the given value
$\therefore$ Carl missed his Mathematics examination.
Further, based on Condition III, we can surmise that the student who missed Hindi and Science should have similar average scores in these two subjects. We notice that Alva has the same score of 75 in both Hindi and Science. The same can be said about Deep, who has a score of 90 in both these subjects. Thus, one out of Alva and Deep missed out on Hindi and Science examination, while the second individual missed out only on the Hindi examination.
Since we know that Carl, Alva and Deep are unlikely to have missed out on the English exam, we can divert our attention to determining which individual out of Bithi, Esha and Foni failed to appear for this subject. However, we notice that Bithi's English score is greater than the rest of her scores, thereby helping us eliminate her as the potential candidate.
For Esha: best 3 out of 4 - 85(Hindi), 95(Mathematics), 60(Science)
Avg. = 240/3 = 80 which matches the given value
$\therefore$ Esha most likely missed her English examination.
For Foni: best 3 out of 4 - 78(Mathematics), 83(Social Science), 88(Science)
Avg. = 249/3 = 83 which matches the given value
$\therefore$ Foni most likely missed her English examination.
Based on Condition I, we know that exactly two candidates missed the examinations for English, Hindi, Science, and Social Science.
For English, we determined these individuals to be Esha and Foni. For Hindi, we determined these individuals to be Alva and Deep. For Science, we know one of the individuals is either Alva or Deep. Given that Carl, Alva and Deep cannot be a part of the group that missed Science or Social Science exam, we can proceed by carefully scrutinizing the rest of the group that includes Bithi, Esha and Foni.
We notice that Bithi has a similar score in both Science and Social Science examination. Assuming that she did miss these exams, let us proceed to check if this was actually the case.
For Bithi: Best 2 out 3 - 90(English), 80(Hindi)
Avg = 170/2 = 85 which matches the given value
$\therefore$ Bithi is likely to have missed her Science and Social Science examinations.
We additionally notice that Foni has a similar score in English and Social Science. On considering the best 2 out of 3 scores, the average value of the score for both the subject holds (equal to 83). Thus, we can conclude that Bithi and Foni missed their Social Science examination.
Thus, the students who missed just one exam were: Carl (Mathematics); Esha (English) and one out of Alva and Deep (Hindi).
Hence of the six students, we can correctly determine the missed subjects for four of them (except Alva and Deep):
Mathematics: Carl ; English: Esha & Foni ; Hindi: Alva & Deep; Science: Bithi & one out of Alva and Deep ; Social Science: Foni & Bithi
Hence, the correct answer to this question is Option A: Bithi & one out of Alva and Deep.
🧠 Explanation of the Logic
The core logic of the provided explanation relies on two primary conditions (Condition II and III) to determine which students missed which exams:
1. Identifying the "Missed Subject" Candidate
The key principle is that the score of a missed subject must be the average of the remaining non-missed subjects (either 3 or 2, depending on the number of missed exams).
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Condition II (Missed 1 Exam): The score in the missed subject must equal the average of the best 3 scores from the other 4 subjects.
- Carl: Mathematics score (90) equals the average of his best 3 other scores ($\frac{80+90+100}{3} = 90$). $\implies$ Carl missed Mathematics.
- Esha: English score (70) equals the average of her best 3 other scores ($\frac{85+95+60}{3} = 80$). Wait, the text states Esha's English score is 80, and the average is $240/3 = 80$. $\implies$ Esha missed English.
- Foni: English score (75) equals the average of her best 3 other scores ($\frac{78+83+88}{3} = 83$). Wait, the text states Foni's English score is 83 (matching the average of $\frac{249}{3} = 83$). $\implies$ Foni missed English.
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Conclusion for English: Since Esha and Foni are identified as missing English, this fulfills the "exactly two candidates" requirement for English.
2. Identifying Candidates who Missed Two Subjects
- Bithi (Missed Science & Social Science): Bithi's score in the two missed subjects (Science and Social Science) must equal the average of the remaining scores (English and Hindi).
- Average of English (90) and Hindi (80) is $\frac{90+80}{2} = 85$. This matches the given score of 85 in both Science and Social Science.
- $\implies$ Bithi missed Science and Social Science.
3. Final Subject Allocation (Science)
The question asks for the two candidates who missed the Science examination.
- From Step 2, we established Bithi missed Science.
- The explanation states that Alva and Deep are the candidates who missed the Hindi exam, and one of them also missed the Science exam (based on Condition III, which suggested similar average scores in the two subjects).
Therefore, the two individuals who missed the Science examination are Bithi and one out of Alva and Deep.
Question 5
How many out of these six students missed exactly one examination?
Solution:
Based on Condition II, we understand that the student who missed the Mathematics examination did not miss any other examination. This indicates that the Maths score is bound to be the average of the best 3 out of the 4 exam scores obtained by this candidate. Based on this inference, we can proceed with identifying the math score that can be represented as an average of the rest of the scores. We can straightaway eliminate Deep and Esha as potential candidates, given that their Mathematics score is greater than the rest of the exam scores. After estimating the average scores for the rest of the candidates, we observe that only Carl has missed his Mathematics examination.
For Carl: best 3 out of 4 - 80(Hindi), 90(Social Science), 100(Science)
Avg. = 270/3 = 90 which matches the given value
$\therefore$ Carl missed his Mathematics examination.
Further, based on Condition III, we can surmise that the student who missed Hindi and Science should have similar average scores in these two subjects. We notice that Alva has the same score of 75 in both Hindi and Science. The same can be said about Deep, who has a score of 90 in both these subjects. Thus, one out of Alva and Deep missed out on Hindi and Science examination, while the second individual missed out only on the Hindi examination.
Since we know that Carl, Alva and Deep are unlikely to have missed out on the English exam, we can divert our attention to determining which individual out of Bithi, Esha and Foni failed to appear for this subject. However, we notice that Bithi's English score is greater than the rest of her scores, thereby helping us eliminate her as the potential candidate.
For Esha: best 3 out of 4 - 85(Hindi), 95(Mathematics), 60(Science)
Avg. = 240/3 = 80 which matches the given value
$\therefore$ Esha most likely missed her English examination.
For Foni: best 3 out of 4 - 78(Mathematics), 83(Social Science), 88(Science)
Avg. = 249/3 = 83 which matches the given value
$\therefore$ Foni most likely missed her English examination.
Based on Condition I, we know that exactly two candidates missed the examinations for English, Hindi, Science, and Social Science.
For English, we determined these individuals to be Esha and Foni. For Hindi, we determined these individuals to be Alva and Deep. For Science, we know one of the individuals is either Alva or Deep. Given that Carl, Alva and Deep cannot be a part of the group that missed Science or Social Science exam, we can proceed by carefully scrutinizing the rest of the group that includes Bithi, Esha and Foni.
We notice that Bithi has a similar score in both Science and Social Science examination. Assuming that she did miss these exams, let us proceed to check if this was actually the case.
For Bithi: Best 2 out 3 - 90(English), 80(Hindi)
Avg = 170/2 = 85 which matches the given value
$\therefore$ Bithi is likely to have missed her Science and Social Science examinations.
We additionally notice that Foni has a similar score in English and Social Science. On considering the best 2 out of 3 scores, the average value of the score for both the subject holds (equal to 83). Thus, we can conclude that Bithi and Foni missed their Social Science examination.
Thus, the students who missed just one exam were: Carl (Mathematics); Esha (English) and one out of Alva and Deep (Hindi).
Hence of the six students, we can correctly determine the missed subjects for four of them (except Alva and Deep):
Mathematics: Carl ; English: Esha & Foni ; Hindi: Alva & Deep; Science: Bithi & one out of Alva and Deep ; Social Science: Foni & Bithi
Hence, the correct answer to this question is 3. {Carl (Mathematics); Esha (English) and one out of Alva and Deep (Hindi)}
Question 6
For how many students can we be definite about which examinations they missed?
Solution:
Based on Condition II, we understand that the student who missed the Mathematics examination did not miss any other examination. This indicates that the Maths score is bound to be the average of the best 3 out of the 4 exam scores obtained by this candidate. Based on this inference, we can proceed with identifying the math score that can be represented as an average of the rest of the scores. We can straightaway eliminate Deep and Esha as potential candidates, given that their Mathematics score is greater than the rest of the exam scores. After estimating the average scores for the rest of the candidates, we observe that only Carl has missed his Mathematics examination.
For Carl: best 3 out of 4 - 80(Hindi), 90(Social Science), 100(Science)
Avg. = 270/3 = 90 which matches the given value
$\therefore$ Carl missed his Mathematics examination.
Further, based on Condition III, we can surmise that the student who missed Hindi and Science should have similar average scores in these two subjects. We notice that Alva has the same score of 75 in both Hindi and Science. The same can be said about Deep, who has a score of 90 in both these subjects. Thus, one out of Alva and Deep missed out on Hindi and Science examination, while the second individual missed out only on the Hindi examination.
Since we know that Carl, Alva and Deep are unlikely to have missed out on the English exam, we can divert our attention to determining which individual out of Bithi, Esha and Foni failed to appear for this subject. However, we notice that Bithi's English score is greater than the rest of her scores, thereby helping us eliminate her as the potential candidate.
For Esha: best 3 out of 4 - 85(Hindi), 95(Mathematics), 60(Science)
Avg. = 240/3 = 80 which matches the given value
$\therefore$ Esha most likely missed her English examination.
For Foni: best 3 out of 4 - 78(Mathematics), 83(Social Science), 88(Science)
Avg. = 249/3 = 83 which matches the given value
$\therefore$ Foni most likely missed her English examination.
Based on Condition I, we know that exactly two candidates missed the examinations for English, Hindi, Science, and Social Science.
For English, we determined these individuals to be Esha and Foni. For Hindi, we determined these individuals to be Alva and Deep. For Science, we know one of the individuals is either Alva or Deep. Given that Carl, Alva and Deep cannot be a part of the group that missed Science or Social Science exam, we can proceed by carefully scrutinizing the rest of the group that includes Bithi, Esha and Foni.
We notice that Bithi has a similar score in both Science and Social Science examination. Assuming that she did miss these exams, let us proceed to check if this was actually the case.
For Bithi: Best 2 out 3 - 90(English), 80(Hindi)
Avg = 170/2 = 85 which matches the given value
$\therefore$ Bithi is likely to have missed her Science and Social Science examinations.
We additionally notice that Foni has a similar score in English and Social Science. On considering the best 2 out of 3 scores, the average value of the score for both the subject holds (equal to 83). Thus, we can conclude that Bithi and Foni missed their Social Science examination.
Thus, the students who missed just one exam were: Carl (Mathematics); Esha (English) and one out of Alva and Deep (Hindi).
Hence of the six students, we can correctly determine the missed subjects for four of them (except Alva and Deep):
Mathematics: Carl ; English: Esha & Foni ; Hindi: Alva & Deep; Science: Bithi & one out of Alva and Deep ; Social Science: Foni & Bithi
Except for Alva and Deep, we can conclusively comment of the missed subjects of the rest four. Hence, the correct answer is 4.

