You are not answering the questions that are being asked. They are asking for probabilities.
We do not do your homework for you. Although it might take more effort to do the work on your own, you will profit more from your effort. We will be happy to evaluate your work though. However, here is a start.
Rewording the questions can be helpful.
3b. Only one will be a boy.
If the events are independent, the probability of both/all events occurring is determined by multiplying the probabilities of the individual events.
3c. 2, 3, or 4 boys.
Either-or probabilities are found by adding the individual probabilities.
4b. All would be black.
4c. 3 or 4 would be red, or 1 or 2 would be black.
14. 2, 3, or 4 girls.
3. A couple is planning on having four children. Assume that the probabilities of the man fathering a boy or a girl are .50 and .50, respectively. What is the probability that
a. exactly two will be boys,
b. fewer than two will be boys, and
c. more than one will be a boy?
Answer
c. more than one will be a boy
4. You draw three cards (with replacement) from a standard deck of cards. What is the probability that
a. exactly one will be red,
b. none will be red, and
c. more than two will be red?
Answer
b. none will be red
14. Assume a man has a .50 chance of fathering a boy and a .50 chance of fathering a girl. He father three children. What is the probability that
a. all three will be girls,
b. exactly two will be girls, and
c. at least two will be girls?
Answer
c. At least two will be girls
4 answers
A couple intends to have 4 children. Assume that having a boy and having a girl are equally likely events. Find the probability that the couple has two boys and two girls.
50
25