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 7 days |
50 cents a day |
After 7 days |
80 cents a day |
Justin rented 4 books and was charged $33.20. How many days did he rent the books for?
$1 = 100¢
$33.20 = 33.20 x 100 = 3320¢
Amount that Justin paid for each book
= 3320 ÷ 4
= 830¢
Amount that Justin paid for each book for renting for the first 7 days
= 7 x 50
= 350¢
Additional amount that Justin paid for each book for renting for additional days
= 830 - 350
= 480¢
Number of additional days that Justin rented for each book
= 480 ÷ 80
= 6
Total number of days that Justin rented the books
= 7 + 6
= 13
Answer(s): 13