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CUET · MATHS · PYQ PAPER 2025

If \(A=\{1,2,3,4, \cdots, n\}\) and \(B=\{x, y\}\), then the number of surjections from \(A\) to \(B\) is

  1. A \(2^n-1\)
  2. B \(2^n-2\)
  3. C \({ }^n P_2\)
  4. D \(n!\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(2^n-2\)

Step-by-step Solution

Detailed explanation

Total functions from \(A\) to \(B\) = \(|B|^{|A|} = 2^n\). Functions that are not surjections map all elements of \(A\) to only one element of \(B\): All map to \(x\): 1 function. All map to \(y\): 1 function. Number of non-surjective functions = \(1+1=2\). Number of surjections…
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