📐 Mathematics · Permutations and Combinations · JEE

How many 2-digit numbers can be formed from digits 1,2,3,4,5 without repetition?

Answer: 20.

Correct answer: B. 20

Explanation: 5P2 = 5×4 = 20 arrangements (order matters, different 2-digit numbers).

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

Concept context

Counting, arrangements, and selections