I've answered (a) & (b), but don't understand (c) of this question

A goal of U.S. airports handling international flights is to clear these flights within 45 minutes. Lets interpret this to mean that 95% of the flights are cleared in 45 minutes, so 5% of the flights take longer to clear. Lets also assume that the distribution is approximately normal.

(a)	If the standard deviation of the time to clear an international flight is 5 minutes, what is the mean time to clear a flight? (Round z-score computation to 2 decimal places and finalanswer to 2 decimal places.)

Mean 36.75

(b)	Suppose the standard deviation is 10 minutes, not the 5 minutes suggested in part (a). What is the new mean? (Round z-score computation to 2 decimal places and finalanswer to 1 decimal place.)

New Mean 28.5

(c)	A customer has 30 minutes from the time her flight lands to catch her limousine. Assuming a standard deviation of 10 minutes, what is the likelihood that she get her luggagein time? (Round z-score computation to 2 decimal places and final answer to 4 decimal places.)

Probability (how do I calculate this?)