Question

how many two digit numbers are divisible by 5

Answer 1

10, 15,....., 95
As it is in A.P
first term, a = 10;
common difference,d = 5
last term, l = 95
T(l) = a + (n-1)d = 95
=> 10 + (n-1)5 = 95
=> (n-1) = (95-10)/5 = 85/5 = 17
=> n - 1 = 17 => n = 17+1 = 18
There are 18 terms of two digit numbers that are divisible by 5.