devarshi-dt-logo

Question:

A debate club consists of 6 girls and 4 boys. A team of 4 members is said to be selected from this club including the selection of a captain (from among these 4 members) for the team. If the team has to include at most one boy, then the number of ways of selecting the team is?

260

320

95

380

Solution:

Given that there is at most one boy in the group of 4. Therefore the selection of 4 members team has 2 possibilities. They are

  1. all 4 members are girls,
  2. 3 girls and 1 boy
    From the first possibility we can select 4 members in 6C4 = 15 ways
    From the second possibility we can select 4 members in 6C3 × 4C1 = 20 × 4 = 80 ways
    Therefore we can select 4 members in 15 + 80 = 95 ways
    Captain can be selected from the group of 4 members in 4C1 = 4 ways
    Therefore, the number of ways of selecting a team of 4 members including the selection of captain is 95 × 4 = 380