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 ?

• A. 9
• B. 18
• C. 31
• D. 46

Answer 1

Answer: (D)

46

Answer 2

Number of ways of selecting one or more friends from 5 friends
$=5C_1+5C_2+5C_3+5C_4+5C_5$
$=5+10+10+5+1=31$ ways
Number of ways of selecting one or more friends from 4 friends
$=4C_1+4C_2+4C_3+4C_4$
$=4+6+4+1=15$ ways
Total ways $=31+15=46$ ways
The correct option is (D)