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 |
30 cents a day |
After 9 days |
40 cents a day |
Tom rented 3 books and was charged $18.90. How many days did he rent the books for?
$1 = 100¢
$18.90 = 18.90 x 100 = 1890¢
Amount that Tom paid for each book
= 1890 ÷ 3
= 630¢
Amount that Tom paid for each book for renting for the first 9 days
= 9 x 30
= 270¢
Additional amount that Tom paid for each book for renting for additional days
= 630 - 270
= 360¢
Number of additional days that Tom rented for each book
= 360 ÷ 40
= 9
Total number of days that Tom rented the books
= 9 + 9
= 18
Answer(s): 18