Given as
The total number of questions = 5
The total number of questions to be answered = 4
The number of ways = we need to answer 2 questions out of the remaining 3 questions as 1 and 2 are compulsory.
= 3C2
On using the formula,
nCr = n!/r!(n – r)!
3C2 = 3!/2!(3 - 2)!
= 3! / (2! 1!)
= [3 × 2 × 1] / (2 × 1)
= 3
Hence, the no. of ways answering the questions is 3.