In a row, 'A' is the 11th position from the left and 'B' is in the 10th position from the right. If 'A' and 'B' interchange, then 'A' becomes 18th from the left. How many persons are there in the row other than 'A' and 'B'?
- A.27
- B.26
- C.25
- D.24
▶ Answer & Explanation
Correct answer: C. 25
When 'A' and 'B' interchange their positions, 'A's new position from the left is given as 18th. Since 'A' was initially 11th from the left, and 'B' was 10th from the right, the interchange means 'A' now occupies 'B's original position. This implies 'A' is now 10th from the right. With 'A' being 18th from the left and 10th from the right, the total number of people in the row is (18 + 10 - 1) = 27. The question asks for persons other than 'A' and 'B', so we subtract 2 from the total: 27 - 2 = 25.
Source: UPSC csat 2014