Question

A bag contains 4 red marbles and 5 blue marbles. What is the probability of randomly selecting a blue marble and then, without replacing it, selecting a red marble?
A. 5/18
B.40/81
C.16/81
D.1/6




Help please

Answer 1

Okay so lets set up our equation...

4 red marbles
5 blue marbles
So the odds are simply 5/9.

If he takes one blue out there is now 4 blues and 4 reds, So the odds of pulling a red now are 4/8 = 1/2.

All you need to do now is multiply the first 2 ratios together to get the combined odds. (5/9)(1/2) = 5/18

So your answer is 5/18 

Hope this helped. Good luck!