Ex 6.4, 4 - Chapter 6 Class 11 Permutations and Combinations

Transcript

Ex 6.4, 4 In how many ways can a team of 3 boys and 3 girls be selected from 5 boys and 4 girls? Selecting 3 Boys We have to select 3 boys from 5 boys Here, n = 5 & r = 3 Number of ways = nCr = 5C3 = 5!/3!(5 −3)! = 5!/3!2! = 10 Selecting 3 girls Similarly we have to select 3 girls from 4 girls Here n = 4 & r = 3 Number of ways = nCr = 4C3 = 4!/(3!(4 −3)!) = (4 × 3!)/(3! × 1!) = 4 Hence, Total number of ways = 10 × 4 = 40 Hence, 40 ways to selecting 3 boys & 3 girls from 5 boys & 4 girls