math probability about number of balls in bag

Question

there are 30 balls, 15 red, 5 yellow, 5 green, and 5 blue a ball is taken out at random and replaced 300 times a/ how many times would you expect to get a red ball? b/ a yellow or blue ball? c/ a ball not blue? d/ a pink ball?

Answer 1

30 balls, 15 red, 5 yellow, 5 green, 5 blue

In general, probability = # ways you want / # of ways total

a) P(red) = 15/30 = 0.5 >> you get an average of 0.5 red balls per draw.

300 draws * 0.5 red / draw = 150 red balls.

b) P(yellow or blue) = 10/30 = 1/3 >> you get an average of 1/3 yellow or blue balls per draw.

300 draws * 1/3 yellow or blue / draw = 100 yellow or blue balls.

c) P(not blue) = 25/30 = 5/6 >> you get an average of 5/6 not-blue balls per draw.

300 draws * 5/6 not-blue balls = 250 not-blue balls

d) P(pink) = 0/30.  There are no pink balls.

Answer 2

none because there are no red balls