According to an NRF survey conducted by BIG research, the average family spends about $237 on electronics (computers, cell phones, etc.) in back-to-college spending per student. Suppose back-to-college family spending on electronics is normally distributed with a standard deviation of $54. If a family of a returning college student is randomly selected, what is the probability that:
a. They spend less than $150 on back-to-college electronics?
b. They spend more than $400 on back-to-college electronics?
c. They spend between $120 and $185 on back-to-college electronics?