We know that, the total number of subsets of a set having n elements is 2n.
⇒2m−2n=56
⇒2n(2m−n−1)=23×7
⇒2n=23 and 2m−n−1=7
⇒n=3 and 2m−n=8
⇒n=3 and m−n=3
⇒n=3 and m=6
Distance between P(6,3) and Q(−2,−3) is given by,
PQ=(6+2)2+(3+3)2
⇒PQ=82+62
⇒PQ=100
⇒PQ=10 units