Final answer:
The probability that a randomly selected classroom at Green Valley High School is for math or history is 17/25, which simplifies to 0.68.
Step-by-step explanation:
The probability that a randomly chosen classroom is for math or history at Green Valley High School can be calculated by adding the probability of selecting a math classroom to the probability of selecting a history classroom, since these are mutually exclusive events. We have a total of 11 math classrooms, 8 science classrooms, and 6 history classrooms, making a total of 25 classrooms.
To find the probability of picking either a math or history classroom, we calculate:
P(Math) = Number of math classrooms / Total number of classrooms
P(History) = Number of history classrooms / Total number of classrooms
P(Math or History) = P(Math) + P(History)
So we have:
P(Math) = 11 / 25
P(History) = 6 / 25
P(Math or History) = (11 / 25) + (6 / 25) = 17 / 25
Therefore, the probability that a randomly chosen classroom is for math or history is 17/25 or 0.68.