Question

A box contains 7 red, 8 green, 12 black and 9 yellow colored balls. If 2 balls are selectedwithout replacement, what is the probability that 1 green and 1 is yellow?

Answer 1

Given

7 red

8 green

12 black

9 yellow

7+8+12+9 = 36 total balls.

The probability of getting 1 green and 1 yellow without replacement is

`\begin{gathered} P(GY)=\frac{\text{number of green}}{\text{total number of balls}}\cdot\frac{\text{number of yellow}}{\text{total number of balls LEFT}} \\ \\ P(GY)=\frac{\text{8}}{36}\cdot(9)/(35) \\ P(GY)=(72)/(1260) \\ P(GY)=(2)/(35) \end{gathered}`

Therefore, the probability is 2/35.