Question

A jar contains 54 marbles bach of which is in one of the colours blue, green and white the probability and the probability of drowing a blue marble is 1/3 draw a green marble 4/9 how many white marble does the are contain

Answer 1

A jar contains 54 marbles bach of colours blue, green and white

let say blue marbles = b

let say green marbles = g

and white marbles =.w

b + g + w = 54

probability of drawing blue marble = b/(b+g+w) = b /54 = 1/3

hence b = 18

blue marbles = 18

probability of drawing green marble = g/(b+g+w) = g/54 = 4/9

hence g = 24

green marbles = 24

b + g + w = 54

18 + 24 + w = 54

w = 12

white marbles = 12

other way

probability of white marble = 1 - (probability of green + probability of blue)

= 1 -(1/3 + 4/9)

= (1/9)×(9 - (3+4))

= (1/9)×2

= 2/9

probability of w = white marbles/ 54

white marbles/ 54 = 2/9

white marbles = 12