A is 16th from the left end in a row of boys and V is 18th from the right end. G is 11th from A towards the right and 3rd from V towards the right end. How many boys are there in the row?

(a) 40
(b) 41 ✓ UPSC's answer
(c) 42
(d) Cannot be determined due to insufficient data

Why the answer is (b)

• A is 16th from the left, so there are 15 boys to A's left.

• G is 11th from A towards the right, meaning G's position from the left is 16 + 11 = 27th.

• G is 3rd from V towards the right end, which implies V is 3 positions to the left of G.

• Therefore, V's position from the left is 27 - 3 = 24th.

• V is also given as 18th from the right end.

• Total boys = V's position from left + V's position from right - 1 = 24 + 18 - 1 = 41.

Why the other options are wrong

(a) 40: Option 40 is incorrect because the calculated total is 41, not 40.
(c) 42: Option 42 is incorrect because the calculated total is 41, not 42.
(d) Cannot be determined due to insufficient data: Option 'Cannot be determined' is incorrect because the positions of A, G, and V provide sufficient data to calculate the exact total.

Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2020, held on 4 October 2020. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.