Question

Jenny read 18 books in 21 weeks. The

diagram shown can be used to track her
progress. If Jenny read at the same rate
each week, how many books had Jenny
read in 7 weeks? In 14 weeks?

Answer 1

6, 12

Explanation:

You actually don't need to find a unit rate for this. You know that 21 is divisible by 7 and 14 is a multiple of 7. If you write the fractions like this:

`(Books)/(weeks)`, then:
`(18)/(21)\\` is the first piece of info given. We next need to find how many books she reading 7 weeks, and we know that 21÷3=7, so:

`(18)/(21)\\`÷
`(3)/(3)`=
`(6)/(7)`. 7 is the number of weeks, 6 is the number of books. Then to find 14 weeks we know that 7×2 is 14, so:

`(6)/(7)`×
`(2)/(2)`=
`(12)/(14)`. 14 is the number of weeks, 12 is the number of books.

Hope this helps!

Answer 2

6 books in 7 weeks

12 books in 14 weeks

Explanation:

We can first create a ratio:

18:21

Now we can simplify it:

6:7

She can read 6 books in 7 weeks.

If we want to find how many she reads in 14 weeks we multiply the ratio by 2.

12:14

She can read 12 books in 14 weeks.