Easy INTEGER +4 / -1 PYQ · JEE Mains 2020

Set A has m elements and set B has n elements. If the total number of subsets of A is 112 more than the total number of subsets of B, then the value of m.n is ______.

Answer (integer) 28

Solution

Number of subsets of A = 2<sup>m</sup> <br><br>Number of subsets of B = 2<sup>n</sup> <br><br>Given = 2<sup>m</sup> – 2<sup>n</sup> = 112 <br><br>$\therefore$ m = 7, n = 4 (2<sup>7</sup> – 2<sup>4</sup> = 112) <br><br>$\therefore$ m $\times$ n = 7 $\times$ 4 = 28

About this question

Subject: Mathematics · Chapter: Sets, Relations and Functions · Topic: Sets and Operations

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