Explanation:
Probability of A is 10 + 5 =15
Probability of B is 9 + 5 ( but you already counted the '5')
so just count 9
9+ 15 = 24
this is 24 out of 16 + 10 + 5 + 9 = 40
or 24/40 which reduces to 3/5 or .6 or 60%
Using the equation given:
P(A) + P(B) - P(A and B)
15 + 14 - 5 = 24 this is out of the entire number 40
24/40 = same as above