Answer :
we have
For interval 15-24
Values -----> 20,15,19
Frequency ----> 3
the next interval is
[25-34]
Values -----> 30,32,27,33,32,
frequency -----> 5
next
[35-44]
Values -----> 39,44,40,38
frequency ----> 4
next
45-54
Values -----> 45,53,45,48,54
frequency -----> 5
next
55-64
Values ----> 62,64,60,54
frequency ----> 4