Question

Find the no of natural numbers between 101 and 999 which are divisible by 2 and 5

Answer 1

first term= 110 , common difference =10, last term=990

Last term = first term +(n-1)×common difference

990=110+(n-1)×10

990-110=10n-10

n=890/10=89

There are 89 natural numbers b/w 101 and 999 that are divisible by both 2 and 5