Jatin is 9th from the front, so there are 8 boys in front of him.
Let the total number of boys be n.
The number of boys behind Jatin =n−9
Given that there were thrice as many behind him as in front:
n−9=3×8
n−9=24
n=33
Therefore, there are 33 boys in total.
The fifth boy from the end is at position:
Position from front =33−5+1=29
So the fifth boy from the end is 29th from the front.
Jatin is at position 9 from the front.
The fifth boy from the end is at position 29 from the front.
Number of boys between them =29−9−1=19
Therefore, there are 19 boys between Jatin and the fifth boy from the end.