math
posted by alice .
A basket contains 15 red numbered balls and 10 white numbered balls. A sample of five balls is selected. How many samples contain three red balls and two white balls? Explain your answer.

you want to choose 3 of the 15 reds and 2 of the 10 whites
Number of ways = C(15,3) x C(10,2)
= 455(45) = 20475