Rideshare services are available internationally where a customer uses a smartphone app to request a ride. Then a driver receives the request, picks up the customer, and takes the customer to the desired location. No cash is involved; the payment for the transaction is handled digitally. Suppose we collect a sample of weekly income of 30,000 rideshare drivers, based on which we get the mean of the weekly income equal to $1500 and standard deviation of $200.

(3 marks for each question below)

a) What is the z value of income for a driver who earns $1600 per week?

b) Among the 30,000 drivers, how many of them have a weekly income of more than $1600?

c) How many of them have a weekly income in between $1400 and $1800?