All 29 people are standing in a row facing North. Peter is 11th from the right end while Robin is 9th from the left end. How many people are there between Peter and Robin?

Given: 

All 29 people are standing in a row facing North.

Peter is 11th from the right end while Robin is 9th from the left end.

Solution:

Peter’s position from the left:

Since total = 29 and Peter is 11th from right:

Peter's position from the left = 29 – 11 + 1 = 19

Robin’s position from the left = 9

Difference = 19 – 9 = 10

Number of people between them = 10 – 1 = 9

9 people are there between Peter and Robin.

Thus, correct option is (d).