CAT 2002 — QA Question 45

∵ pqr = 1

Case 1:

Let p = 2/3, q = 3/2 and r = 1

Substituting the values of p, q, r, we get,

$\frac{1}{1+p+q^{-1}}+\frac{1}{1+q+r^{-1}}+\frac{1}{1+r+p^{-1}}=\frac{3}{7}+\frac{2}{7}+\frac{2}{7}=1$

Case 2:

Let p = 1, q = 1 and r = 1

Substituting the values of p, q, r, we get,

$\frac{1}{1+p+q^{-1}}+\frac{1}{1+q+r^{-1}}+\frac{1}{1+r+p^{-1}}=\frac{1}{3}+\frac{1}{3}+\frac{1}{3}=1$

Hence, option (c).