Alpha Airline claims that only 15% of its flights arrive more than 10 minutes late. Let p

Question:

Alpha Airline claims that only 15% of its flights arrive more than 10 minutes late. Let p be the proportion of all of Alpha’s flights that arrive more than 10 minutes late. Consider the hypothesis test
H0: p < .15 versus H1: p > .15
Suppose we take a random sample of 50 flights by Alpha Airline and agree to reject H0 if 9 or more of them arrive late. Find the significance level for this test.