Most credit card holders pay off their debt promptly, to avoid paying interest. However, sometimes, this is not possible. Interest paid monthly on credit card debt is normally distributed, with a mean of $38 and a standard deviation of $4.

a) What is the probability that credit card holders pay less than $35 in debt? SHOW BASIC WORKINGS.

b) What interest payment caps the lowest 0.25% of all credit card holders?

SHOW BASIC WORKINGS.

c) If you are now told that interest paid monthly is positively skewed, can you trust your answer to part a)? Briefly explain.