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A box contains some black balls and 30 w...

A box contains some black balls and 30 white balls. If the probability of drawing a black ball is two fifths of a white ball, then the number of black balls in the box is

A

6

B

12

C

18

D

30

Text Solution

Verified by Experts

The correct Answer is:
B
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Knowledge Check

  • A bag contains 15 white balls and some black balls. If the probability of drawing a black ball is thrice that of a white ball, find the number of black balls in the bag.

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