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