a is chosen from the set {1,2,3,4,5}, and b is chosen from the set {5,6,7,8,9}. What is the probability that the product ab is a prime number?
a is chosen from the set {1,2,3,4,5}, and b is chosen from the set {5,6,7,8,9}. What is the probability that the product ab is a prime number?
There can be 5 x 5 products. 25 possible
For the product to be a prime numer,
a must be 1 and b must be either 5 or 7. 2 possible
Probability of the product being a prime is 2 / 25.
