Answer:
C. 5 weeks.
Step-by-step explanation:
In this question we have a random variable that is equal to the sum of two normal-distributed random variables.
If we have two random variables X and Y, both normally distributed, the sum will have this properties:
To calculate the expected weeks that the donation exceeds $120, first we can calculate the probability of S>120:
The expected weeks can be calculated as the product of the number of weeks in the year (52) and this probability:
The nearest answer is C. 5 weeks.