You were charged $51.50 last month for data usage on your smartphone. your data plan charges a monthly fee of $20 plus $2.50 for each extra gigabyte (gb) used. how many extra gigabytes did you use last month?

Liang bought a basket of apples to make pies for her friends. the basket of apples weighed p pounds. before she had time to make the pies, she ate 3 pounds of apples. there are 17 pounds of apples left to make pies.