Organizers of a televised fundraiser know from past experience that most people donate small amounts ($10$25), some

Question:

Organizers of a televised fundraiser know from past experience that most people donate small amounts ($10—$25), some donate larger amounts ($50-$ 100), and a few people make very generous donations of $250, $500, or more. Historically, pledges average about $32 with a standard deviation of $54.
a) If 120 people call in pledges, what are the mean and standard deviation of the total amount raised?
b) What assumption did you make in answering this question?