CAT 2018 Slot 2 QA Question & Solution
AlgebraMedium
Question
If p$^{3}$ = q$^{4}$ = r$^{5}$ = s$^{6}$, then the value of $log_{s}{(pqr)}$ is equal to
Options
$\frac{47}{10}$
$\frac{24}{5}$
$\frac{16}{5}$
$1$
Solution
Given that, p$^{3}$ = q$^{4}$ = r$^{5}$ = s$^{6}$
p$^{3}$=s$^{6}$
p = s$^{\frac{6}{3}}$ = s$^{2}$ ................................(1)
Similarly, q = s$^{\frac{6}{4}}$ = s$^{\frac{3}{2}}$ .........(2)
Similarly, r = s$^{\frac{6}{5}}$ ......................(3)
$\Rightarrow$ $log_{s}{(pqr)}$
By substituting value of p, q, and r from equation (1), (2) and (3)
$\Rightarrow$ $log_{s}{(s^{2}*s^{\frac{3}{2}}*s^{\frac{6}{5}})}$
$\Rightarrow$ $log_{s}(s^{\frac{47}{10}})$
$\Rightarrow$ $\dfrac{47}{10}$
Hence, option A is the correct answer.
