Question

a bag cantain 15 white ans some black ball if the probability of Drawing black ball from bag is thrice that of Drawing a white ball, find no. of black ball in a bag

Answer 1

If the number of white balls ie 15, is taken as x, then no of black balls will be 3x ie 15 × 3 = 45. if probability is also asked, it's 45/(15+45), 3/10.