Home > Statistics > Conditional Probability

Dr. Sox drives through two stoplights on her way to work. The first light is green for 20 seconds out of each minute. The second light is green for 35 seconds out of each minute. What is the probability that Dr. Sox will hit two green lights?

Answer 1

Cameron Adams

Since this is an AND situation, we MULTIPLY the probabilities.

First light green: #P_1=20/60=1/3#

Second light green: #P_2=35/60=7/12#

Both lights green: #P=P_1xxP_2=1/3xx7/12=7/36#

Of course, this is assuming that there is no "green wave" policy, or the two probabilities would not be independent.

By signing up, you agree to our Terms of Service and Privacy Policy

Answer 2

Greyson Taylor

To find the probability of Dr. Sox hitting two green lights, multiply the probabilities of each light being green:

Probability of first light being green = 20/60 = 1/3 Probability of second light being green = 35/60 = 7/12

Probability of both lights being green = (1/3) * (7/12) = 7/36

By signing up, you agree to our Terms of Service and Privacy Policy

Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.