📐 Mathematics · Permutations and Combinations · JEE

Number of injective (one-to-one) functions from A (3 elements) to B (4 elements):

Answer: 4P3 = 24.

Correct answer: D. 4P3 = 24

Explanation: Injective: no two elements of A map to same element in B. 4P3 = 4×3×2 = 24.

Counting tree for selecting 2 items from {A, B, C} without repetition: 3 x 2 = 6 ordered arrangements.

Concept context

Counting, arrangements, and selections