5.84 An ice-cream truck has an average daily profit of £250 with a standard deviation of £40.

a. If a random business day is selected, what is the probability that the day’s profit is more than £280?

b. If a random business day is selected, what is the probability that the day’s profit is between £240 and £265?

c. What is the minimum amount of profit required for a day to be considered among the top 10% of most profitable business days?

d. If a random sample of 200 business days is selected, what is the probability that at least 60 days have earned a daily profit of more than £280?

e. If 2 business days are randomly selected, what is the probability that at least one day has a profit of more than £280?