. The route used by a driver in commuting to work contains two intersections with traffic signals. The probability that he must stop at the first signal is .4, the analogous probability for the second...

. The route used by a driver in commuting to work contains two intersections with traffic signals.

The probability that he must stop at the first signal is .4, the analogous probability for the second

signal is .5, and the probability that he must stop at one or more of the two signals is .6. What is

the probability that he must stop

(a) At both signals?

(b) At the first signal but not at the second one?

(c) At exactly one signal?