📐 Mathematics · Permutations and Combinations · JEE

Number of ways to distribute 5 identical balls into 3 distinct boxes:

Answer: 21.

Correct answer: B. 21

Explanation: Stars and bars: C(5+3-1, 3-1) = C(7,2) = 21.

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

Concept context

Counting, arrangements, and selections