A jar contains 24 marbles, some are green and others are blue. If a marble is drawn at random from the jar, the probability that it is green is 2/3.

Total number of marbles = 24
Let the total number of green marbles be x.
Then, total number of blue marbles 24 – x
P (getting a given marble) = x/24
According to the condition given in the question,
x/24 = 2/3
⇒ x = 16
Therefore, total number of green marbles in the jar = 16
Hence, total number of blue marbles = 24 – x = 24 – 16 = 8