Question

A bag contains white and red balls sum to 45 balls.Find the number of red balls if probability of choosing a white ball is 2/9​

Answer 1

Given Number of white balls $$=4

Let Number of red balls =N

then total balls =N+4

Probability of drawing a white ball from the bag would be

P(whiteball)=

Totalballs

Numberofwhiteballs

=

n(Total)

n(white)

=

N+4

4

But Given P(whiteball)=

5

2

So P(whiteball)=

5

2

=

N+4

4

5

2

=

N+4

4

2(N+4)=5∗4

2N+8=20

2N=20−8=12

N=6

So the number of red balls in the bag is 6 red balls.