Question

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

Answer 1

Let the total number of balls be x.

probability of black balls is given by = total black balls/total number of balls

it is given as 2/5

so 2/5 = 20/x

so x = 50.

hence the total number of balls is 50