Suppose the average reaction time for a driver is 400 ms with standard deviation 100 ms, and assume reaction time is normally distributed. (a) Find the probability that a random driver's reaction time is between 250 ms and 550 ms. (b) Suppose three cars are closely following one another when the first car suddenly stops. If greater than 1 s of lag time (i.e. the sum of the two trailing driver reaction times) occurs, there will be a collision either between the first two or second two cars. What is the probability of a crash?