Question

3. A bag contains 5 red balls and some blue balls if the probability of drawing blue ball is
double that of red ball then find the number of blue balls in the bag.
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Answer 1

10 blue balls will be in the bag

Answer 2

Let number of blue balls in the bag =x

Total no of balls in bag =5+x [No. of redball =5]

Probability of drawing a blue ball = No. of blue ball /

Total no of ball

P(B)= X/5+x

Probability of drawing a Red ball = No. of red ball/

Total no of ball

P(R)= 5/5+x

Given,

P(B)=2P(R)

X/(5+X)=2*(5/(5+x)

x=10

Hence, no. of blue balls in the bag =10