Answer:
The probability to draw two red balls = 1/22
The probability to draw one red ball = 9/22
The probability to draw no red ball = 12/22
Step-by-step explanation:
Number of Red balls = 3
Number of White balls = 9
If the player draws two red balls, he receives $4
If the player draws one red ball, he receives $1
If the player draws no red ball, he looses $2
The total number of balls = 3+9
= 12
Let R represent Red balls
Let W represent White balls
The probability that the player earns $4 by picking two red balls is represented as Pr(R1 n R2)
Pr(R1 n R2) = Pr(R1) * Pr(R2)
Pr(R1) = 3/12
= 1/4
Pr(R2) = 2/11(we assume he draws without replacement)
Pr(R1 n R2) = 1/4*2/11
= 2/44
= 1/22
The probability of earning $4 is 1/22
The probability of drawing one red ball is Pr(R1 n W2) or Pr(W1 n R2)
Pr(R1) = 3/12
= 1/4
Pr(W2) = 9/11
Pr(W1) = 9/12
= 3/4
Pr(R2) = 3/11
Pr(R1 n W2) or Pr(W1 n R2) =
(1/4 * 9/11) + (3/4 * 3/11)
= (9/44) + (9/44)
= 18/44
= 9/22
Therefore, the probability of earning $1 is 9/22
The probability that no red ball is chosen is Pr(W1nW2)
Pr(W1) = 9/12
= 3/4
Pr(W2) = 8/12
Pr(W1nW2) = 3/4 * 8/11
= 24/44
= 12/22
therefore. the probability of loosing $2 is 12/22