Page 208 - Algebra 1

Example
5
Application: Trucking
Mr. Jackson drove a truck 300 miles in 6 hours. If he drives at a constant speed, how long will it take him to drive 450 miles?
SOLUTION
Let x represen_t the number of hours it will take to drive 450 miles. rate = distance
Set up a proportion.
Write cross products. Solve.
Math Reasoning
Estimate It takes
5.75 hours to drive about 300 miles. How long will it take to drive about
580 miles at the same rate?
300 miles = 450 miles __
6 hours x hours 300 · x = 450 · 6 300x = 2700 x=9
time
Mr. Jackson will drive 450 miles in 9 hours.
Lesson Practice
Practice
Distributed and Integrated
Simplify.
1. 7-4-5+12-2-⎢-2
(10)
2. -6·3+⎢-3(-4+23) (11)
a.
(Ex 1)
b.
(Ex 2)
c.
(Ex 2)
Which is the better buy: 8 boxes for $4.96 or 5 boxes for $3.25?
A chemist raised the temperature of a liquid 45°F in 1 minute. What is this amount in degrees Fahrenheit per second?
Jamie typed 20 pages of a document in 2 hours. How many pages did she type in 1 minute?
Solve each proportion.
_ _ e. 5 =10
(Ex 3) _ _ d.c=3
f.
(Ex 4)
g.
(Ex 4)
h.
(Ex 5)
n+2 16
The ratio of blue chips to red chips in a bag is 5:7. The bag has 60 chips
in all. How many blue chips and how many red chips are in the bag?
A map shows a 5.5-inch distance between Orange City and Newtown, and a 3.75-inch distance from Newtown to Westville. The scale on the map is 1 inch:100 miles. What is the actual distance, if you drive from Orange City via Newtown to Westville?
If Jeff walks 4 miles in 48 minutes, how far can he walk in 72 minutes?
7 21
Lesson 31 193