Probo from set theory

Two finite sets have m and n elements. The total number of subsets of the first set is 56 more than the total number of subsets of the second set. Find the value of m and n.
This is a qestion from fiitjee s material. Mobile se pucha hai. So pls work it out.

6 Answers

36
rahul ·

No one wow!!!!!!

1
mohit sengar ·

no of elements in m = 6 and n = 3

21
Shubhodip ·

It's clear that the first set has 2m subsets and second one has 2n subests.

so we have to solve 2m - 2n = 56 (m,n are positive integers)

Its also clear that m>n

let m = k+n

so 2k+n- 2n= 56

2n(2k- 1)= 23*7

clearly 2k-1 is odd

so 2n= 23, and n = 3

and 2k-1= 7 so k =3

so m = 3+3 = 6 and n = 3

;O)

36
rahul ·

Thanks shubhodip bhai! I worked it out by hit and trial method but ur's have some logic.

6
AKHIL ·

hit and trial se ho gaya na!!

bas theek hai!!
:P

but good job shubhodip....:)

21
Shubhodip ·

thnk u :P

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