How many two digit numbers are divisible by 5 such that reminder is 1.
The two-digit numbers which leave the remainder 1 when divided by 5
11,16,21,26,.......86,91,96
In this A.P :
a=11
d=16−11=5
l=96
An=a+(n−1)d
96=11+(n−1)5
n−1=855
n=17+1
n=18
Hence 18 two digit numbers are divisible by 5 such that reminder is 1.