Q35 of 53 Page 15

A bag contains 5 red balls and some blue balls. If the probability of drawing a blue ball from the bags is four times that of a red ball, find the number of blue balls in the bag.

Let the number of blue balls be X


So total number of balls = 5 + X


P(probability of drawing a red ball from the bag) =


P(probability of drawing a blue ball from the bag)=


ATQ ,


=


=


5X +X2 = 100+20X


X2 - 15X+ -100 = 0


(x-20)(x+5) =0


So X -5


Therefore No. Of blue balls = 20


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