A jar contains 54 marbles each of which is blue , green or white. The probability of selecting a blue marble at random from the jar is 1/3 and the probability of selecting a green marble at random is 4/9 . How many white marbles does the jar contain? (Ans:12)
Ans: Let there be b blue, g green and w white marbles in the marbles in the jar. Then, b + g + w = 54
∴ P (Selecting a blue marble) = b/54
It is given that the probability of selecting a blue marble is 1/3 .
∴ 1/3 = b/54 => b = 18
We have,
P(Selecting a green marble) = 4/9
=> g/54 = 4/9
[Q P (Selecting a green marble) = 4/9 (Given)]
=> g = 24
Substituting the values of b and g in (i), we get
18 + 24 + w = 54 => w = 12