Math 8 Percent, Ratio, and Rate
Rate.
Name:________________
Date:_________________
Block:_________
Lesson 5.9: Exploring Rates.
Making Connection
Connection::
Canadian speed skater Jeremy Wotherspoon, of Red
Deer, Alberta, set the world record for the 500 m at the
2004 World Cup in Italy. He skated at an average speed
of 14.44 m/s. The white-tailed deer can run at speeds of
up to 30 km/h.
Who is faster? How can you find out?
When we compare two things with different units, we have a rate.
Here are some rates:
a) We need 5 sandwiches for every 2 people.
b) Oranges are on sale for $1.48 for 12.
c) Gina earns $4.75 per hour for baby-sitting.
d) There are 500 sheets on one roll of paper towels.
The last two rates are unit rates. Each rate compares a quantity to 1 unit.
Jamal skipped rope 80 times in 1 min. We say that Jamal's rate of skipping is
80 skips per minute. We write this as: 80 skips/min
skips/min.
Example 1) Express as a unit rate.
a) The bus travelled 80 km in 2 h.
b) Marco’s heart beats 35 times in 30 s.
c) Inga walked 12 km in 4 h.
d) Wally washed 20 plates in 4 min.
e) Cherie delivered 150 catalogues in 2.5 h.
Example 2) A printing press prints 120 sheets in 3 min.
a) Express the printing as a unit rate.
b) How many sheets are printed in 1 h?
c) How long will it take to print 1000 sheets?
Example 3) a) A human walks at an average speed of 5 km/h. What is this speed in
metres per second?
b) A squirrel can run at a top speed of about 5 m/s. What is this speed in
kilometres per hour?
Example 4) Sal earns $24 in 3 h. Josh earns $13 in 2 h. Komal earns $44 in 4 h.
a) Who makes the most money per hour?
b) How much will the person who earns the most money per hour earn in 8 h?
Example 5) a) Fran bought 3 cans of soup for $1.47. At this rate, how much will 7
cans cost?
b) James read 48 pages in 90 min. How many pages could he read in 4.5 h?
Example 6) A 300-g package of pepperoni costs $4.29.
a) What is the cost per 100 g?
b) How much would 1 kg cost?
c) How much pepperoni could you buy with $20?