Question

A bag contains 10 marbles: 2 are green, 3 are red, and 5 are blue. Abdul chooses a marble at random, and without putting it back, chooses another one at random. What is the probability that the first marble is red and the second is blue? Write your answer as a fraction in simplest form.

Answer 1

Answer:

1/6

Step-by-step explanation:

P(x) = probability that event x happens

It's commonly known that P(A & B) (so that both A and B happen) = P(A) * P(B).

so

P(red, then blue) = P(red) * P(blue shifted)

The probability that you pick a red marble first is 3/10 because there are 10 equally likely outcomes, and you pick a red marble in 3 of them.

The probability that you pick a blue marble next is 5/9 because there are now 9 marbles left, and 5 of them are blue.

Multiplying these together results in 3/10*5/9=15/90=1/6.