📐 Mathematics · Permutations and Combinations · JEE

Number of ways to select at least one from n objects:

Answer: 2ⁿ - 1.

Correct answer: B. 2ⁿ - 1

Explanation: Total subsets = 2^n. Excluding empty set: 2ⁿ - 1 ways to select at least one object.

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

Concept context

Counting, arrangements, and selections