Let the total number of subset in set A=2m and subset in s B=2n According to the given condition, 2m=2n+56 ⇒2m−2n=56 ⇒2n(2m−n−1)=8×7 ⇒2n(2m−n−1)=23×(23−1) On comparing both sides, we get n=3 and m−n=3 ⇒m−3=3 ⇒m=6 So, m=6 and n=3