Exercise 21 Page 288

We want to know the number of books Alexis had read in 4 and 8 weeks if she read at the same rate each week. To do this, we will use the information in the graph to calculate the unit rate.

15books/12weeks or 15/12 To find the unit rate, we write an equivalent rate with a denominator of 1.

15/12

ReduceFrac

a/b=.a / 12./.b / 12.

15÷ 12/12÷ 12

CalcQuot

Calculate quotient

1.25/1

The unit rate is 1.25 books read per week. Now, we can use the unit rate to find how many books Alexis had read in 4 weeks.

1.25/1

ExpandFrac

a/b=a * 4/b * 4

1.25* 4/1* 4

Multiply

Multiply

5/4

The number of books read in 4 weeks is 5. We do the same thing for 8 weeks.

1.25/1

ExpandFrac

a/b=a * 8/b * 8

1.25* 8/1* 8

Multiply

Multiply

10/8

The number of books read in 8 weeks is 10. Finally, we can complete the diagram.