A box contains 10 black and 10 white balls. What is the probability of drawing 2 balls of the same colour? `9/(19)` (b) `9/(38)` (c) `(10)/(19)` (d) `5/(19)` (e) None of these

A bag contains 10 white, 6 black and 4 red balls. Find the probability of getting : a black ball

A bag contains 10 white, 6 black and 4 red balls. Find the probability of getting : a white ball

A box contains 3 red, 4 black and 5 white balls. Three balls are drawn at random. Then the probability of 2 white balls and 1 red ball is

A box contains 10 balls which are numbered 0 to 9. If one ball is drawn unseen, the probability of drawing a number greater than 6 is

If three balls drawn from a bag contains are 4 red,3 black and 5 white balls.The probability of drawing 2 balls of the same colour and one is of different colour is

A box contains 20 electric bulbs,out of which 4 are defective.Two balls are chosen at random from this box.The probability that at least one of them is defective,is (4)/(19) (b) (7)/(19) (c) (12)/(19) (d) (21)/(95) (e) None of these

A box contains some black balls and 30 white balls. If the probability of drawing a black ball is two-fifths of a white ball, find the number of black balls in the box.