The waiting time at a supermarket checkout counter has an exponential distribution with an average waiting time of 5 minutes. The probability density function f(x)= .2e^(-.2x) is shown in Figure. To find areas under this curve, you can use the fact that P(x>a)= e^(-.2a) for a>0. What is the probability that you have to wait 10 minutes or more at the checkout counter?