Grade 8 - Unit Five

Fractions, Decimals & Percents Name: ______

Here is a collection of sports balls:

A ratio can be used to compare quantities. A two-term ratio compares 2 quantities: For example, the ratio of basketballs to tennis balls is 7 to 8. There are three ways to write two-term ratios:

Basketballs to tennis ball: 1) using “to” 7 to 8

2) using “:” 7 : 8

3) as a fraction

A part-to-whole ratio compares one quantity to the total number of items. For example, what is the ratio of golf balls to all of the balls?

Answer: 5 to 20, 5 : 20 or .

A three-term ratio compares three quantities. There are 2 ways to write three-term ratios. For example, what is the ratio of tennis balls to basket balls to golf balls?

Answer: 8 to 7 to 5 or 8 : 7 : 5

a) What is the ratio of golf balls to basket balls? ______

b) What is the ratio of basket balls to all balls? ______

c) What ratio does 5 : 7 :8 represent? ______

Here are some shapes:

a) What is the ratio of stars to flowers? (Write three ways) ______,

______, ______

b) What is the ratio of happy faces to all shapes? What is this ratio called? ______,

______

c) What ratio does 5 : 3 : 4 represent? ______

d) What is the ratio of flowers to stars? ______

e) What is the ratio of stars to happy faces to all shapes? ______

Equivalent ratios are like equivalent fractions. To find an equivalent ratio, multiply or divide each term by the same number:

Ex/ 2 : 3 is equivalent to 6 : 9. Each term is multiplied by 3. 2 : 3 = 6 : 9

15 : 5 : 10 is equivalent to 3: 1 : 2. Each term is divided by 5.

Complete the following by finding an equivalent ratio for each of the following.

a) 2 : 4 / b)
c) 3 : 5 : 1 / d) 18 : 9 : 27

Find the missing number in each pair of equivalent ratios:

a) 5 : 4 = : 8 / b)
c) 1 : : 5 = 8 : 24 : 40 / d)

1) The ratio of hot dogs to hamburgers sold at a BBQ was 7:3.

a) If 77 hotdogs were sold, how many hamburgers were sold?

b) If a total of 100 items were sold, how many hot dogs were sold? How many hamburgers were sold?

2) There are 32 students in a grade 8 class. The ratio of boys to girls is 5 : 3

a) How many boys are in the class?

b) How many girls are in the class?

Ms Mandeville makes her coffee with
2 scoops of coffee for every 5 cups of water. / Ms Hodder makes her coffee with
3 scoops of coffee for every 7 cups of water.

Whose coffee is stronger? Find out how many cups of water per scoop

Ratio of water to scoop:

Ms Mandeville
5 : 2
You want to know how much water per scoop so divide by 2:
2 : 1
/ Ms Hodder
7 : 3
You want to know how much water per scoop so divide by 3:
2 : 1

Since 2 is less than 2 , Ms. Hodder uses less water per scoop, so her coffee is stronger.

The recommended seeding on a package of grass seed is 200 g per 9 m2. Mr Foss spread 150 g over 6.5 m2. Did Mr Foss spread enough grass seed?

Find out how many grams per 1m2 were recommended, then find out how many grams per 1 m2 Mr Foss used.

Recommended
Ratio grams to m2
200 : 9
You want to know how many grams per m2 so divide by 9.
/ Mr Foss
Ratio grams to m2
150 : 6.5
You want to know how many grams per m2 so divide by 6.5.
23.1 : 1

Since the recommended is about 22.2g per m2 and Mr Foss used 23g per m2, Mr Foss used more than enough grass seed.

A rate compares things with different units:

Ex/ John travels at 120 km every 2 hours. In this example, we are comparing distance (km) and time (hours)

It the second quantity in the rate is 1, then we have a unit rate.

Ex/ Since John travels 120 km every 2 hours, The unit rate is 60 km every hour. This is written as

1. Are the following rates or ratios?

a)Kayla earns $33 for 3 hours of snow clearing. ______

b)Ms Sceviour mixes 3 scoops of dark blue paint with 2 scoops of white paint in order to make light blue paint. ______

c)A&W is selling 2 teen burgers for $5. ______

d)Mr Thistle can type 30 words each second. ______

e)The best way to make fruit punch is to have six apples for every pineapple. ______

2. Write the unit rate for each of the following:

a)Jill made $45 babysitting for 5 h. ______

b)12 apples cost $1.25.______

c)A car travels 140km in 3h.______

d)A human heart beats 140 times in 2 minutes.______

e)A dozen Pepsi costs $8.25.______

1. Which box of garbage bags is the better buy?

Write a unit rate for each:

Box A Box B

Box B is the better buy since each bag only costs $0.11.

2. Which package of paper towels is the better buy?

Write a unit rate for each:

Package APackage BPackage C

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