probabilty distribution

Question

At Buzz’s Hair Dressing Salon 40% of the clients are male.

On a particular day 125 clients come into the store, calculate the probability that fewer than 40 of them are male.

Answer 1

40% of 125 is 50 males

npq= var = 125(.4)(.6) = 30 sd = sqr 30 = 5.48

less than 40 is almost 2 sd from mean so about 2.5% chance

there's another way to do this though, as soon as my wifi connection stops fading