If and , then

If there are n objects to be arranged in circular order the no of permutations possible=
First we will make the 5 girls around the table and this can be done in , different ways
Now we have 5 places available between these girls and the 5 boys can be seated in these 5 available places in , different ways
Hence the 5 boys and 5 girls can be arranged in ways


Let A and B be two sets having m and n elements respectively.Then,
Number of subsets of A=2m,Number of subsets of B=2n
It is given that 2m-2n=56
so,2n(2m-n-1)=23(23-1)
n=3 and m-n=3n=3 and m=6