There are 3 sections in a question paper and each section contains 5 questions. A candidate has to answer a total of 5 questions, choosing at least one question from each section. Then the number of ways, in which the candidate can choose the questions, is:

Step-by-step solution

A → 5 Q    B → 5 Q    C → 5 Q A 1 , A 2 , A 3 , A 4 , A 5    B 1 , B 2 , B 3 , B 4 , B 5 C 1 , C 2 , C 3 , C 4 , C 5 A 1 A 2 A 3 B 1 C 1 ⇒ C 1 3 × C 3 5 × C 1 5 × C 1 5 = 750 , where three questions are picked from any of the subject and one each from other two subjects. A 1 A 2 B 1 B 2 C 1 ⇒ C 2 3 × C 2 5 × C 2 5 × C 1 5 = 1500 , where one question is picked from one of the subject and two each from rest of the two subjects.