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 |
90 cents a day |
Ian rented 4 books and was charged $21.60. How many days did he rent the books for?
$1 = 100¢
$21.60 = 21.60 x 100 = 2160¢
Amount that Ian paid for each book
= 2160 ÷ 4
= 540¢
Amount that Ian paid for each book for renting for the first 9 days
= 9 x 40
= 360¢
Additional amount that Ian paid for each book for renting for additional days
= 540 - 360
= 180¢
Number of additional days that Ian rented for each book
= 180 ÷ 90
= 2
Total number of days that Ian rented the books
= 9 + 2
= 11
Answer(s): 11