Question

Questions 5-6: An American roulette wheel contains 18 red slots, 18 black slots, and 2 green slots.

5. If you spin the wheel twice, find the probability of landing on a black slot both times: *

(A) 0.2244

(B) 0.25

(C) 0.4737

(D) 0.5263

6. If you spin the wheel twice, find the probability of landing on one red and one green, when order does not matter. (Hint: You could get red first and then green or green first and then red!): *

(A) 0.0499

(B) 0.4737

(C) 0.0249

(D) 0.5783

Answer 1

No. of red slots = 18

No. of black slots = 18

No. of green slots = 2

Total slots =18+18+2 = 38

5. Landing on black slots both times= 18C2 = 152

Landing on two slots =38C2 = 703

Probability of landing on black slots both times = 18C2/38C2 = 152/703 = 0.23

6. Landing on one red and one green, when order does not matter = (18C1*2C1) + (2C1*18C1) = (18*2) +(2*18) = 40

Landing on two slots =38C2 = 703

Probability of landing on one red and one green, when order does not matter = 40/703 = 0.06