CAT Exam Model Paper 3 with solutions for free online practice

(c) The harmonic mean of two numbers x and y is

2xy

(x+y)

and the geometric mean is √xy.
∴

( 2xy x+y )

√xy

=

12

13

,
squaring both sides, we get

2xy

(x+y)2

=

144

169

. Although this can be simplified to get the answer, the best way to proceed from here would to look out for the answer choices and figure out which pair of x and y satisfies the above equation. You will find the answer is (c).