3 digit numbers that are divided by 4 are : 100,104,108,................,992,996 Above series is an A.P. with first term, a=100, common difference , d=4 and last term , l=996 Thus, nth term of an A.P., An=a+(n−1)d ⇒ 100+(n−1)4=996 ⇒ (n−1)×4=996−100=896 ⇒ (n−1)=
896
4
=224 ⇒ n=224+1=225 ∴ There are 225 three digit numbers that are divided by 4.