Since we are trying to find the probability of a sequence of events we simply need to multiply the probability of each of these events happening separately from one another. We are told that the probability that the light will be red is 65% that means that the probability that it will be green and that the driver will not need to stop is 35%. This probability remains the same every day of the week. Therefore we need to multiply this probability 5 times, one time for each weekday Monday through Friday, but first we need to turn this percentage into a decimal form by dividing it by 100...
35% / 100 = 0.35
0.35 * 0.35 * 0.35 * 0.35 * 0.35 = 0.00525 ...multiply by 100 to get percentage
0.00525 * 100 = 0.525%
Finally, we can see that the probability that she will not have to stop at the light all next week is 0.525%
