Answer:
Step-by-step explanation:
Given that X is the number of months between successive payments
Cumulative distribution function of X is

a) PMF of x would be

b) 
The order is 1/6, 4/19, 1/2, 7/12, 7/12, and 2/3.
Answer:
20
Step-by-step explanation:
Associative property (associative laws)