Answer:
Let's break down the problem step by step:
(a) List all possible arrangements of girls (G) and boys (B) for a family planning to have three children:
1. BBB
2. BBG
3. BGB
4. GBB
5. BGG
6. GBG
7. GGB
8. GGG
(b) List the sample space for X, which is the possible values that X (the number of boys) may take:
X can take on the values: 0, 1, 2, 3
(c) To find the probability that X=1, we need to count the number of outcomes where there is exactly 1 boy (B) and 2 girls (G). From the list in part (a), we can see that there are three such outcomes: BBG, BGB, and GBB. There are a total of 8 possible outcomes. So, the probability that X=1 is 3/8.
(d) To find the probability that the couple has three boys (X=3), we need to count the number of outcomes where all three children are boys (BBB). There is only one such outcome, and there are still 8 possible outcomes in total. So, the probability that the couple has three boys is 1/8.
Explanation: