Mary used Delicious (d) and Golden Delicious (g) apples to make homemade applesauce. Delicious apples are $0.75 each and Golden Delicious apples are $1.25 each. Mary spent $21.00 on 22 apples. What should the second equation be?

d + g = 21

g – d = 21

0.75d + 1.25g = 21

0.75d – 1.25g = 21