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Number of one-one functions from {1, 2, 3} to {a, b, c, d, e}:
A125
B5
CP(5, 3) = 60 (choose 3 of 5, arrange)
D3!
Answer & Solution
Correct answer: C. P(5, 3) = 60 (choose 3 of 5, arrange)
Injective function from n-element set to m-element set (n ≤ m): P(m, n) = m!/(m-n)!. P(5, 3) = 5 × 4 × 3 = 60. Each input maps to distinct output.
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