What percentage of male athletes wears contact lenses during performances?

What percentage of male athletes wears contact lenses during performances? Let p be the proportion of male athletes who wear contact lenses. A) If you have no preliminary estimate for p, how many male athletes should you include in a random sample to be 90% sure that a point estimate ^P will be within a distance of 0.05 from p?

B) Studies show that approximately 19% of male athletes wear contact lenses during performances. Answer part a) using this estimate for p.