In a box there are 28 marbles of which x are green and the rest are white. If the probability of getting a green marble is 2 then the number
In a box there are 28 marbles of which x are green and the rest are white. If the probability of getting a green marble is 2 then the number of white marbles is
A) 20
B) 16
C) 12
D) 8
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Correct option is: A) 20
Total No. of marbles in the box is 28.
There are x green marbles and rest are white.
\(\therefore\) Total No. of white marbles = 28 - x
Probability of getting a green marble = \(\frac 27\)
\(\therefore\) \(\frac x{28} = \frac 27\)
\(\Rightarrow\) x = \(\frac 27 \times 28 = 2 \times 4 = 8\)
\(\therefore\) Total No. of white marbles = 28- x = 28-8 = 20
Hence, there are 20 white marbles in the box.
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