# Here is the Solution

# PROBABILITY

The probability of a car passing a certain intersection in a 20 minute windows is 0.9. What is the probability of a car passing the intersection in a 5 minute window? (Assuming a constant probability throughout)

**SOLUTION : **Let x be the probability of a car passing the intersection in a 5 minute window. Therefore, Probability of a car passing in a 20 minute window = 1 – (probability of no car passing in a 20 minute window)

Probability of a car passing in a 20 minute window = 1 – (1 – probability of a car passing in a 5 minute window)^4

Solving this, we get x = 1 – 10^(-0.25) = 0.4377