Multiple choice

How many onto (or subjective) functions are there from an n-element (n $\ge$ 2) set to a 2-element set?

  1. 2n

  2. 2n – 1

  3. 2n – 2

  4. 2(2n-2)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total number of functions is 2n, out of which there will be exactly two functions where all elements map to exactly one element, so total number of onto functions is 2n – 2.

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