A box contains x red balls and 10 black balls. 3 balls are drawn one by one without replacement. If the probability of choosing 3 red balls is equal to the probability of choosing 2 red and 1 black ball, then the possible value of x can be

Question

A box contains x red balls and 10 black balls. 3 balls are drawn one by one without replacement. If the probability of choosing 3 red balls is equal to the probability of choosing 2 red and 1 black ball, then the possible value of x can be, 1, 32, 53, 40

MARKS App · Accepted Answer

Probability of choosing 3 red balls = x C 3 10 + x C 3 Probability of choosing 2 red balls and one black ball = x C 2 10 C 1 10 + x C 3 So, x C 3 10 + x C 3 = x C 2 10 C 1 10 + x C 3 ⇒ x C 3 = x C 2 10 C 1 ⇒ x C 3 x C 2 = 10 ⇒ x - 3 + 1 3 = 10 ⇒ x = 3 2

Search any question & find its solution

Looking for more such questions to practice?