A bag of balloons contain 2 red balloons, 1 green balloon, 17 yellow balloons, and 8 orange balloons. What is the probability that a randomly selected balloon would be green or orange?

I got 9/28, but I think that's wrong

yes

9/28 is right.

To find the probability of selecting a green or orange balloon, you need to divide the number of green and orange balloons by the total number of balloons.

Let's first calculate the total number of balloons:
2 (red) + 1 (green) + 17 (yellow) + 8 (orange) = 28.

The number of green or orange balloons is 1 (green) + 8 (orange) = 9.

So, the probability of selecting a green or orange balloon is:
9 (green or orange) / 28 (total) = 9/28.

Therefore, your initial answer of 9/28 is indeed correct. Well done!