JAMB - Mathematics (2000 - No. 36)
In how many ways can a delegation of 3 be chosen from among 5 men and 3 women, if at least one man and at least one woman must be included?
15
28
30
45
Giải thích
No of ways of choosing 1 man, 2 women = 5C1 x 3C2
No of ways of choosing 2 men, 1 woman = 5C2 x 3C1
Summing, => (5C1 x 3C2) + (5C2 x 3C1) = 15 + 30 = 45
No of ways of choosing 2 men, 1 woman = 5C2 x 3C1
Summing, => (5C1 x 3C2) + (5C2 x 3C1) = 15 + 30 = 45