Xavier Aptitude Test 2013 Paper

(c) As p, q, r are non-negative integers, the maximum will be achieved when the value of each variable is closed to each other.
i.e. p, q, r are 3, 3, 4 (not necessarily in the same order).
Hence the value of
pq + qr + pr + pqr = 3 × 3 + 3 × 4 + 3 × 4 + 3 × 3 × 4 = 9 + 12 + 12 + 36 = 69