SOLUTION: Every hour a certain traffic light is green for 45 min, orange for 1 minutes and red for 14 minutes. A taxi passes the same traffic light 9 times a day. 1. What is the probabilit

Question 1138941: Every hour a certain traffic light is green for 45 min, orange for 1 minutes and red for 14
minutes. A taxi passes the same traffic light 9 times a day.
1. What is the probability that the light is green on all occasions?
2. What is the probability that the light is not red on at least 3 occasions.

Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
It is green 3/4 of the time, 45/60
0.75^9=0.0751
not red is 46/60 of the time
for 0 occasions is 0.0915
for 1 is 9*(0.7667^8)*0.02333 (the 9 is the number of different ways 1 can occur)=0.2507
for 2 it is 9C2*0.7667^7*0.2333^2=0.3051
That probability is 0.6473
The complement is at least 3, and that is 0.3527, the answer.
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