Question

How many two digit numbers are divisible by 5 such that reminder is 1.

Answer 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 :

$a=11$

$d=16-11=5$

$l=96$

$A_n=a+(n-1)d$

$96=11+(n-1)5$

$n-1=\frac{85}{5}$

$n=17+1$

$n=18$

Hence 18 two digit numbers are divisible by 5 such that reminder is 1.