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if-two-finite-sets-have-m-and-n-term-if-the-no-of-subset-of-first-set-is-112-more-then-the-no-of-subset-of-second-set-find-m-and-n-




Question Number 69175 by Aditya789 last updated on 21/Sep/19
if two finite sets have m and n term.if the no of subset of first set is 112 more then the no of subset of second set.find m and n?
$${if}\:{two}\:{finite}\:{sets}\:{have}\:{m}\:{and}\:{n}\:{term}.{if}\:{the}\:{no}\:{of}\:{subset}\:{of}\:{first}\:{set}\:{is}\:\mathrm{112}\:{more}\:{then}\:{the}\:{no}\:{of}\:{subset}\:{of}\:{second}\:{set}.{find}\:{m}\:{and}\:{n}? \\ $$
Answered by Rasheed.Sindhi last updated on 21/Sep/19
∣A∣=m , ∣B∣=n  P(A)=2^m  , P(B)=2^n   P(A)−P(B)=2^m −2^n =112  2^m ≥2^7 ⇒m≥7  2^n =2^(m≥7) −112  For m=7  2^n =2^7 −112=16=2^4 ⇒n=4  One solution: (7,4)   I have found out one solution but I  I′m not certain of its uniqueness.
$$\mid\mathrm{A}\mid={m}\:,\:\mid\mathrm{B}\mid={n} \\ $$$$\mathrm{P}\left(\mathrm{A}\right)=\mathrm{2}^{{m}} \:,\:\mathrm{P}\left(\mathrm{B}\right)=\mathrm{2}^{{n}} \\ $$$$\mathrm{P}\left(\mathrm{A}\right)−\mathrm{P}\left(\mathrm{B}\right)=\mathrm{2}^{{m}} −\mathrm{2}^{{n}} =\mathrm{112} \\ $$$$\mathrm{2}^{{m}} \geqslant\mathrm{2}^{\mathrm{7}} \Rightarrow{m}\geqslant\mathrm{7} \\ $$$$\mathrm{2}^{{n}} =\mathrm{2}^{{m}\geqslant\mathrm{7}} −\mathrm{112} \\ $$$${For}\:{m}=\mathrm{7} \\ $$$$\mathrm{2}^{{n}} =\mathrm{2}^{\mathrm{7}} −\mathrm{112}=\mathrm{16}=\mathrm{2}^{\mathrm{4}} \Rightarrow{n}=\mathrm{4} \\ $$$${One}\:{solution}:\:\left(\mathrm{7},\mathrm{4}\right) \\ $$$$\:{I}\:{have}\:{found}\:{out}\:{one}\:{solution}\:{but}\:{I} \\ $$$${I}'{m}\:{not}\:{certain}\:{of}\:{its}\:{uniqueness}. \\ $$

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