Q. A is 16th from the left end in a row or boys and V is 18th from the right end. Q 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
(c) 42
(d) Cannot be determined due to insufficient data
Correct Answer: (b) 41
Question from UPSC Prelims 2020 CSAT Paper
Explanation :
A is 16th from the left end in a row
Problem: Finding total number of boys in a row
Given:
– A is 16th from left end
– V is 18th from right end
– Q is 11th from A towards right
– Q is 3rd from V towards right
Solution:
1. Find Q’s position from left:
– A is 16th from left
– Q is 11th right of A
– So Q is 16 + 11 = 27th from left
2. Find Q’s position from right:
– V is 18th from right
– Q is 3rd right of V
– So Q is 18 – 3 = 15th from right
3. Calculate total boys:
– Q’s position from left = 27
– Q’s position from right = 15
– Total boys = Left position + Right position – 1
– Total = 27 + 15 – 1 = 41 (Subtract 1 because Q is counted twice)
Therefore, there are 41 boys in the row.
