To find the probability that the light will not be green at a randomly chosen time, we need to consider the time when the light is yellow or red.
The total time for one complete cycle of the traffic light is 60 seconds.
The light is green for 25 seconds, yellow for 5 seconds, and red for 30 seconds.
Therefore, the probability that the light will not be green is the sum of the probabilities of it being yellow or red.
Probability of the light being yellow = time for yellow / total time = 5 / 60 = 1 / 12
Probability of the light being red = time for red / total time = 30 / 60 = 1 / 2
Probability that the light will not be green = Probability of being yellow + Probability of being red
= 1/12 + 1/2
= 7/12
Therefore, the probability that the light will not be green at a randomly chosen time is 7/12.