Question

Fifteen billiard balls are numbered 1 to 15. One billiard ball is selected at random. Determine the odds for and the odds against for (6 Points) a) selecting the number 7 b) selecting a number greater than 10

Answer 1

Odds for & against selecting number 7 = 1/14 & 14

Odds for & against selecting number more than 10 = 4/11 & 11/4

Explanation:

Odds for event = Prob (event) / Prob (no event)

Odds against event = Prob (no event) / Prob (event)

• Odds for selecting number 7

Prob (No. 7 chosen) = 1/15 , Prob (No. 7 not chosen) = 14/15

Odds for number 7 = (1/15) ÷ (14/15) = 1/14

Odds against number 7 = (14 / 15) ÷ (1/15) = 14

• Odds for selecting number > 10

Prob (No. > 10 chosen) = 4 / 15 , Prob (No. > 10 not chosen) = 11/15

Odds for No. > 10 = (4/15) ÷ (11/15) = 4/11

Odds against No. > 10 = (11/15) ÷ (4/15) = 11/4