A book rental shop rented out books and the rate of rental charges are shown in the table.
Number of days |
Rates |
After the first 9 days |
40 cents a day |
After 9 days |
70 cents a day |
Ahmad rented 3 books and was charged $17.10. How many days did he rent the books for?
$1 = 100¢
$17.10 = 17.10 x 100 = 1710¢
Amount that Ahmad paid for each book
= 1710 ÷ 3
= 570¢
Amount that Ahmad paid for each book for renting for the first 9 days
= 9 x 40
= 360¢
Additional amount that Ahmad paid for each book for renting for additional days
= 570 - 360
= 210¢
Number of additional days that Ahmad rented for each book
= 210 ÷ 70
= 3
Total number of days that Ahmad rented the books
= 9 + 3
= 12
Answer(s): 12