Answer:
310
Explanation:
The equation that we would use to solve this problem is 7 × 50 - 40 = b
(b is the number of non-yellow balloons)
Since Aaron bought 7 packs of balloons with 50 balloons in each pack, we would need to multiply 7 and 50 to find the total amount of balloons that he bought.
7 × 50 = 350.
Now we subtract 40 (the total number of yellow balloons) from 350 (the total number of balloons), to find the amount of balloons that are not yellow.
350 - 40 = 310