Question

A bag contains 15 white and some black balls. If the probability of

drawing a black ball from the bag is thrice that of drawing a white ball,

find the number of black balls in the bag.

Answer 1

HOLA

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$\frac{x}{x \: + \: 15} \: = \: 3 \: \times \: \frac{x}{x + 15} \: \: = \: 45$


So there 45 black balls

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if U feel this is difficult simply do this ==>

P(E) = 3 × P( Of getting white ball)

= 3 × 15 = 45

HOPE U UNDERSTAND❤❤❤

Answer 2

try it by yourself. .....