In an examination, a student to answer 4 questions out of 5 questions; questions 1 and 2 are however compulsory. Determine the number of ways in which the student can make a choice.

Question

Philoid · Accepted Answer

Given that student have to answer 4 questions from 5 questions.

It is also told that questions 1 and 2 are compulsory.

It is similar to answering the 2 questions out of the remaining 3 questions as 1 and 2 are compulsory.

Let us assume the no. of ways of answering the questions be N.

⇒ N = No. of ways of answering 2 questions from remaining 3 questions.

⇒ N = ³C₂

We know that ,

And also n! = (n)(n – 1)......2.1

⇒

⇒ N = 3

∴ The no. of answering the questions is 3.