Answer:
8 students went to the science museum twice last year.
Explanation:
It's pretty straightforward but just to give an explanation: So based on the graph, it seems like each green x is equal to one student. And on the bottom it tells us the numbers 0-5 are the number of times of trips students took. It tells you to calculate the amount students went EXACTLY twice, so look at how many green x's are at number 2 and that's the answer, 8.