Fast-food profits Mac’s fast-food restaurant finds that its daily profits have a normal distribution with mean

$140 and standard deviation $80.

a. Find the probability that the restaurant loses money on a given day (that is, daily profit less than 0).

b. Find the probability that the restaurant makes money for the next seven days in a row. What assumptions must you make for this calculation to be valid? (Hint:

Use the binomial distribution.)