Let S = 1 ,   2 ,   3 ,   … . , 100 , then number of non-empty subsets A of S such that…

Let S=1, 2, 3, .,100, then number of non-empty subsets A of S such that the product of elements in A is even is :
  1. 2100-1
  2. 250+1
  3. 250250-1
  4. 250-1

Solution

As we know that the product of numbers is even when at least one of the number must be even.

Hence total subsets of A in which product of numbers is even = Total subsets total subsets in which all the elements are odd

=2100-250=250250-1.

Asked in: JEE Main 2019 (12 Jan Shift 1)

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