Question

An urn contains 10 red balls, 6 green balls, 15 orange balls, and 14 blue balls.

If one ball is randomly drawn from the urn, what are the odds against the ball being red?

State your answer as a ratio using a colon to separate the two numbers.

Answer 1

35:45 = 7:9

Answer 2

prob(red) = 10/45 = 2/9
so , prob(not red) = 7/9

odds against red ball
prob(not red) : prob(red)
= (7/9) : (2/9)
= 7 : 2