Another question I need help with.

A drug tester claims that a dnJg cures a rare skin disease 79% of the time. The claim is checked by testing the drug on 100 patients. If at least 77 patients are cured, the claim will be accepted. Find the probability that the claim will be rejected assuming that the manufacturer's claim is tme. Use the normal distribution to approximate the binomial distribution if possible. The probability is I]. (Round to four decimal places as needed.)