Question

A bag contain 15 balls out of which some are white and some are black .If probability of drawing a black ball at random is 2/3.find no.of white balls

Answer 1

Answer: 5 balls

Step-by-step explanation:

The bad contains 15balls

:. n(S)= 15

Now;

There are white and black balls in the bag.

But ; probability of black ball is 2/3

Let A be the event of gettind BLACK ball.

:. P (A) = n(A) / n(S)

= n(A) /15................(n(S)=15)

But P(A) =2/3

:. 2/3 = n(A)/15

:.cross multiplication

:.2*15=3*n(A)

:.30=3*n(A)

:.30/3=n(A)

:.n(A)=10

:. There are 10 black balls

Now;

Therw are 15 balls in bag ; among them now 10are black balla

:.15-10=5

:. Tere are 5 white balls inthe bag.