Question

Find the number between 101 and 999 that is divisible by 2 and 5

Answer 1

Here, we'll use the concept of AP...
The no. divisible by both 5band 2 is 10 only.
Thus, our AP will be,
110, 120 ,130.............990
a=110, d=10 and, àn=990
àn=a+ (n-1)d
990=110 + (n-1)10
880÷10 = n-1
88 + 1=n
Therefore, there will be 89 such no.