Seating (row positions) — swap effect on ranks In a row of children, Ravi is fourth from the right and Sham is second from the left. When they interchange positions, Ravi becomes ninth from the right. What is Sham's position from the left after the swap?

Introduction / Context:Rank/position problems in a line rely on converting “from left/right” ranks into total count and vice versa.

Given Data / Assumptions:

• Ravi initially 4th from right.
• Sham initially 2nd from left.
• After swapping places, Ravi is 9th from right.

Concept / Approach:Use the identity: position_from_right = N − position_from_left + 1, where N is total people.

Step-by-Step Solution:After the swap, Ravi occupies Sham’s old spot: 2nd from left.Given Ravi then is 9th from right ⇒ 9 = N − 2 + 1 ⇒ N = 10.Sham moves to Ravi’s old spot: 4th from right.Convert to left-rank: position_from_left = N − 4 + 1 = 10 − 4 + 1 = 7.

Verification / Alternative check:Enumerate 10 places; confirm indices align with the computed ranks before/after swap.

Why Other Options Are Wrong:They correspond to incorrect totals N or misapplication of the left-right conversion formula.

Common Pitfalls:Forgetting the “+1” when switching between left and right positions.

Final Answer:Seventh