Question

read this attachment and answer pls​

Answer 1

Let number of blue balls in the bag =x

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

Probability of drawing a blue ball =

$\bold{ \frac{No. \: of \: blue \: ball}{Total \: no \: of \: ball} }$

$P(B) = \frac{x}{5 + x}$

Probability of drawing a Red ball =

$\bold{ \frac{No. \: of \: red\: ball}{Total \: no \: of \: ball} }$

$P(R) = \frac{5}{5 + x}$

Given,

P(B)=2P(R)

$= \frac{x}{5 + x} = 2(\frac{5}{5 + x})$

=x=10

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