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  1. GATE CS
  2. PYQs
  3. Discrete Mathematics

Let X and Y denote the sets containing 2 and 20 distinct objects respectively and F denote the set of all possible functions defined from X to Y. Let f be randomly chosen from F. The probability of f being one-to-one is ______.

GATE 2015 · Discrete Mathematics · Functions · medium

Answer: 0.95

  1. Count total functions from X to Y: Total functions = 20^2 = 400
  2. Count injective functions from X to Y: Injective functions = P(20, 2) = 20 * 19 = 380
  3. Compute probability: P = 380 / 400 = 0.95