Same rank from both ends: Sunita is 11th from both the left end and the right end of a row of girls. How many girls are there in the row?

Introduction / Context:
If a person is the k-th from both ends in a single row, the total number is 2k − 1 because the person is counted twice when simply adding.

Given Data / Assumptions:

• Sunita is 11th from left and also 11th from right.

Concept / Approach:
Total N = 2 * 11 − 1.

Step-by-Step Solution:

Verification / Alternative check:
Positions from both ends sum to N + 1 ⇒ 11 + 11 = 22 = N + 1 ⇒ N = 21.

Why Other Options Are Wrong:

• 19, 20, 22: Do not satisfy the symmetry condition 11 + 11 = N + 1.
• None of these: Correct answer available.

Common Pitfalls:
Forgetting to subtract 1 after doubling.

Final Answer:
21