Question

A man has 5 friends and his wife has 4 friends. They want to invite either of their friends, one or more to a party. In how many ways can they do so?

पर्याय

• 9

• 18

• 31

• 46

Answer 1

46
Explanation:
A man can invite the friends in
`""^5C_1+""^5C_2+""^5C_3+""^5C_4+""^5C_5`
= `2^5-1=31` ways
His wife can invite the friends in
`""^4C_1+^""4C_2+""^4C_4+""^4C_4`
= `2^4-1=15` ways
∴ Total number of ways = 31 + 15 = 46