What is prob. exactly 15 have had pizza for breakfast?

3 out of 4 have had cold pizza for breakfast. 20 people are asked.What is prob. exactly 15 have had pizza for breakfast?
0.20233 BY USING THIS;



C(20,15)(.75)^15(.25)^5



FYI: If you were to use the normal approximation to the Binomial you would get 0.197212