Can someone please tell me why the answer for d) is 0.48?

d)

Therefore, P (W>4.2) = 0.5

= = 4.2

ii) P(X>4.2)

P(Z> 4.2-6.6 / 1.2)

p (z>-2) = 0.9772

The probability would be equal to 0.5*0.9772 =0.48

I think this is wrong. please tell me answer will you? The question is below

In a supermarket, there are two cashier counters: a regular counter and an express counter. It is known that 88% of customers pay at the regular counter. It is found that the waiting time for a customer to pay at the regular counter follows the normal distribution with mean 6.6 minutes and standard deviation 1.2 minutes. (a) Find the probability that the waiting time for a customer to pay at the regular counter is more than 6 minutes. (3 marks) (b) Suppose 12 customers who pay at the regular counter are randomly selected. Assume that their waiting times are independent. Find the probability that there are more than 10 of the 12 customers each having a waiting time of more than 6 minutes. (4 marks) It is found that the waiting time for a customer to pay at the express counter follows the normal distribution with mean u minutes and standard deviation 0.8 minutes. It is known that exactly 21.19% the customers pay at the regular counter wait less than k minutes, while exactly 3.59% of the customers at the express counter wait more than k minutes. (c) Find k and u. (4 marks) (d) For a randomly selected customer, given that he waits more than u minutes to pay, find the probability that he pays at the regular counter. (9 marks)