Civil Services Examination · Question 7
How many possible values of (p + q + r) are there satisfying 1/p + 1/q + 1/r = 1, where p, q and r are natural numbers (not necessarily distinct)?
Show answer & explanation
Answer: (C) Three
Explanation
The solutions are (3, 3, 3), (2, 4, 4) and (2, 3, 6), giving sums 9, 10 and 11: three values. (Answer as per the official UPSC answer key.)