Seashell Gas Station

For the Seashell gas station in your neighbourhood, records indicate that the number of customers arriving in any 5-minute interval averages 0.94 customers, with a standard deviation of 0.97 customers. Sixty-five (65) percent of the customers use a credit card to pay for their purchase. There are 8 pumps at this service station. The time that a car is parked at a pump is normally distributed with a mean of 6.35 minutes and a standard deviation of 2.10 minutes. All the above activities are independent of each other.
a) Ninety-four (94) percent of the customers will be parked for what maximum amount of time (Use 2 decimal places rounded.)?
b) For 12 randomly selected customers, what is the probability that at least 10 of them will pay using a credit card? (Use 4 decimal places rounded.)c) What is the probability that more than 5 customers will arrive in a 15-minute period?
(Use 4 decimal places rounded.)
d) What is the probability that the average parked time for the next 40 customers is less than 6 minutes?
(Use 4 decimal places rounded.)

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