The Total solution for NCERT class 6-12
Given:
Total number ofquestions = 5
Total number ofquestions to be answered = 4
Number of ways = weneed to answer 2 questions out of the remaining 3 questions as 1 and 2 arecompulsory.
= 3C2
By using the formula,
nCr = n!/r!(n – r)!
3C2 = 3!/2!(3 -2)!
= 3! / (2! 1!)
= [3×2×1] / (2×1)
= 3
∴ The no. of waysanswering the questions is 3.