Question

A jar contains 24 marbles out of which some are green and others are blue. If a marble is drawn at random from the jar, the probability that it is green is $\frac{2}{3}$. Find the number of blue marbles in the jar.

Answer 1

Total number of marbles in the jar = 24
Let the number of green marbles in the jar be x.
Then, number of blue marbles = ( 24 − x)
Given: P(green marble) =$\frac{2}{3}$
Therefore,
$$\begin{gathered} \frac{x}{24}=\frac{2}{3} \\ \Rightarrow 3x=48 \\ \Rightarrow x=16 \end{gathered}$$
Thus, there are 16 green marbles in the jar and number of blue marbles = 24 − 16 = 8
Hence, the number of blue marbles in the jar is 8.