To find the number of persons sitting between the 9th person from the left and the 16th person from the right, we need to consider two scenarios:

Scenario 1: When the 9th person from the left is sitting to the left of the 16th person from the right.
Scenario 2: When the 9th person from the left is sitting to the right of the 16th person from the right.

Scenario 1: When the 9th person from the left is sitting to the left of the 16th person from the right

In this scenario, we can calculate the number of persons between them by subtracting the sum of their positions from the total number of persons sitting in the row.

Given:
Total number of persons in the row = 30
Position of the 9th person from the left = 9
Position of the 16th person from the right = (30 - 16 + 1) = 15

Number of persons between the 9th person from the left and the 16th person from the right = Total number of persons - (Position of the 9th person + Position of the 16th person)
= 30 - (9 + 15)
= 30 - 24
= 6

Scenario 2: When the 9th person from the left is sitting to the right of the 16th person from the right

In this scenario, we need to consider the positions of the 9th person from the left and the 16th person from the right in reverse order.

Given:
Total number of persons in the row = 30
Position of the 9th person from the left = 30 - 9 + 1 = 22
Position of the 16th person from the right = 16

Number of persons between the 9th person from the left and the 16th person from the right = Total number of persons - (Position of the 9th person + Position of the 16th person)
= 30 - (22 + 16)
= 30 - 38
= -8

Since the number of persons cannot be negative, we discard this scenario.

Therefore, the number of persons sitting between the 9th person from the left and the 16th person from the right is 6.

1 2 3 4 5 6 7 8 9 * * * * * 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
Total 30

Or

You have to find between them
so no need to count 9th from left and 16th from right too
So
30-9=21
21-16= 5 answer