Rates
11-3
6 miles in 1 hour
is called a unit rate.
A rate is a ratio that compares two quantities with
different units of measure. A unit rate is a rate that has
1 unit as its second term, or denominator.
Rates are used almost every day. For example, average
speeds and prices are often given as rates.
Moya ran 18 miles at a steady pace in 3 hours.
Her average speed can be expressed as a ratio:
^1
3
8
h
m
ou
ile
rs
s
18 miles : 3 hours 18 miles in 3 hours
To find how many miles Moya ran in 1 hour, x,
use equivalent ratios.
1
3
8
h
m
ou
ile
rs
s
x
1
m
ho
ile
u
s
r
1
. 3
8
.
3
3
6
1
Moya ran 6 miles in 1 hour, or 6 miles per hour.
Four ballpoint pens cost $2.20.
This rate of cost can be given as a ratio.
^4
$2
p
.
e
2
n
0
s 4 pens : $2.20 4 pens for $2.20
To find the cost of one pen, p, use equivalent ratios.
^4
$2
p
.
e
2
n
0
s ^0
$
.
2
4
.2
..
0
0
4
^4
$.
1
55
One pen costs $.55.
1 pen
p
1 unit
price of 1 unit
total number of units
total price
A unit price is the
cost of one item.
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