Question

A bag contains white,black& red balls only. A ball is drawn at random from the bag. the probablity of grtting a white ball is 3/10 and that of black ball is 2/5.Find the probablity of getting a red ball if bag contains 20 black balls ,then find the total no. of balls in the bag

Answer 1

Step-by-step explanation:

Probability of black ball is 2 out of 5

It there are 20 black ball out of Total no. of balls

Then total numbers of balls (x) =

2/5 = 20/x

5/2 = x/20

x/20 = 5/2

x = (5×20)/2

x = 50

Hence , Total number of balls is 50

Now To find out the number of red balls , we have to know the no. of black balls (= which is 20) & White balls

number of White balls = 3 out of 10

& y out of 50

3/10 = y/50

y/50 = 3/10

y = (3×50)/10

y = 15

No. of white balls = 15

No. of Red balls = Total balls - black balls & - white balls

No. of Red balls = 50 - 20 - 15

= 50 - 35

= 15

& Probability of finding red balls = 15/50 = 3/10