Question

Out of 400 families with 5 children each how many would you expect to have either 2 or 3 boys

Answer 1

Answer:

≈ 134

Step-by-step explanation:

There are total 400 families with 5 children each.

There are total six possibilities of having boys among the five children.

1. 0 boys + 5 girls

2. 0 boy + 4 girls

3. 2 boys + 3 girls

4. 3 Boys + 2 girls

5. 4 boys + 1 girl

6. 5 boys + 0 girls

Thus probability for each possibility is 1/6

∴ Probability for 2 boys = 1/6

∴ Probability for 3 boys = 1/6

Cobine probability for 2 or 3 boys = 1/6 + 1/6 = 2/6 = 1/3

∴ Expected number of families to have either 2 or 3 boys = 400 × 1/3 = 133.33

Rounding off

∴ Expected number of families to have either 2 or 3 boys ≈ 134