Question

In a family, the probability that a child is female is 0.6. if there are thee children in the family, what is the probability that 1. Exactly 2 are girls 2. At least 1 is a boy

Answer 1

Answer:1.P(exactly 2 kids are girls)=3/8

2. P(at least 1 is boy)=7/8

Explanation:

1.P(exactly 2 kids are girls)=N(outcomes with 2 girls) /Total number of outcomes.

All possible outcomes are ggb,gbg, bgg, gbb, bgb, bbg, ggg, bbb - total 8

Outcomes where are exactly 2 girls are:

ggb,gbg, bgg - total 3 outcomes

So P(exactly 2 are girls)=3/8

2. P(at least 1 is boy)=Number of outcomes , where are at least 1 boy (1,2 or all 3 kids are boys)/ Total number of outcomes

All possible outcomes are ggb,gbg, bgg, gbb, bgb, bbg, ggg, bbb - total 8

Outcomes, where at least 1 kid is boy: ggb,gbg, bgg, gbb, bgb, bbg, bbb - total 7

P(at least 1 is boy)=7/8