# Question

A company services copiers. A review of its records shows that the time taken for a service call can be represented by a normal random variable with a mean of 75 minutes and a standard deviation of 20 minutes.

a. What proportion of service calls takes less than 1 hour?

b. What proportion of service calls takes more than 90 minutes?

c. Sketch a graph to show why the answers to parts (a) and (b) are the same.

d. The probability is 0.1 that a service call takes more than how many minutes?

a. What proportion of service calls takes less than 1 hour?

b. What proportion of service calls takes more than 90 minutes?

c. Sketch a graph to show why the answers to parts (a) and (b) are the same.

d. The probability is 0.1 that a service call takes more than how many minutes?

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