If a number is selected at random from each of the sets p = {1, 2, 3} and Q = {2, 3, 5}, find the probability that the sum of the numbers is prime
Answer Details
To find the probability that the sum of the numbers is prime, we need to first determine all the possible sums of numbers from sets P and Q.
The elements in set P are {1, 2, 3}, and the elements in set Q are {2, 3, 5}. To find all the possible sums, we can create a table of sums by adding each element of set P to each element of set Q:
| | 2 | 3 | 5 |
|---|---|---|---|
| 1 | 3 | 4 | 6 |
| 2 | 4 | 5 | 7 |
| 3 | 5 | 6 | 8 |
From this table, we see that there are nine possible sums. To determine which of these sums are prime, we can simply check each one:
- 3: Not prime
- 4: Not prime
- 5: Prime
- 6: Not prime
- 7: Prime
- 8: Not prime
- 9: Not prime
- 10: Not prime
- 11: Prime
So, there are three possible sums that are prime: 5, 7, and 11. Therefore, the probability that the sum of the numbers is prime is:
$$\frac{\text{number of favorable outcomes}}{\text{total number of possible outcomes}} = \frac{3}{9} = \frac{1}{3}$$
Therefore, the answer is option (C) \(\frac{1}{3}\).