Question

Buy 5 get 1 freeNotebooks were sold at $8 each. Marcia spent $120.a) how many free books did she get?b) how many notebooks did she get altogether?c) Mr. Khan got 24 notebooks when he bought some for his children. How much money did he spend?

Answer 1

item a):

Dividing the amount Marcia spent on the notebooks by the unitary price, we can find out how many notebooks she bought. Marcia spent $120, and one notebook costs $8, then, the amount of notebooks she bought is

`(120)/(8)=15`

She bought 15 books. Since every 5 notebooks you buy you get one for free, by dividing the amount of paid notebooks by 5 we get the amount of notebooks you get for free.

Since Marcia bought 15 notebooks, she got

`(15)/(5)=3`

3 notebooks for free.

item b):

Since she bought 15 notebooks and got 3 for free, to find the total we just need to add those values.

`15+3=18`

She got 18 notebooks altogether.

item c):

If you buy 5 you get one free, this means that every 6 notebooks you get one of them is free. If we divide the total amount of notebooks Mr. Khan got by 6, we get the amount of notebooks that were free. Since Mr. Khan got 24 notebooks

`(24)/(6)=4`

Mr. Khan got 4 free notebooks, therefore, he paid for 20 notebooks.

Since he paid for 20 notebooks, to find the value he spent we multiply the amount of paid notebooks by the unitary cost

`20\cdot8=160`

Mr. Khan spent $160.