A produce store sold 63 red apples. If the ratio of red apples to green apples sold was 7:2, what is the combined amount of red and green apples sold?

7/2 = 63/g ... 7 red apples to 2 green apples = 63 red apples to g green apples

cross multiply

(7) (g) = (2) (63)

7g = 126

g = 126/7

g = 18

so they sold 63 red apples and 18 green apples ... for a total of (63 + 18) = 81 apples sold

So if there are 63 red apples / 7 that equals 9 apples per part. That means that There are 7 parts of 9 red apples, which is true, then there are 2 parts of 9 green apples, which equals 18 green apples. 18 + 63 = 81 apples total.