Question

An urn contains 2 white balls, 3 red balls, and 5 blue balls. You draw 3 balls (all at once) from the urn. What is the probability that they are all blue?

Answer 1

Number of white balls in the urn = 2

Number of red balls in the urn = 3

Number of blue balls in the urn = 5

Total number of balls in the urn = 2+3+5 =10

Number of balls drawn from the urn = 3

When 3 balls are drawn from the urn, probability that they are all blue

= Number of ways of drawing 3 blue balls from 5 blue balls / Number of ways of drawing 3 balls from 10 balls

When 3 balls are drawn from the urn, probability that they are all blue = 1/12 = 0.08333333