2. Gas Saving Habits
So you like fast starts and high speeds? Here’s news for you—you’re a gas
guzzler. Your
car may have been advertised with a mileage rate of 30 miles per gallon, but your driving habits
can easily pull the mileage down to 15 MPG. This lesson is all about improving your driving
habits and computing savings on gas.
Gasoline Used at Different Speeds
for the Same Distance
The bar graph at right shows you that for the same distance
speed. Use the graph to answer questions 1–4.
1. a. 8 gallons of gas were used to drive 250 miles at 30
mph (miles per hour). How many gallons were used
at 50 mph?
______________
How many gallons were used at 80 mph?
______________
b. If gas is $1.43 per gallon, how much more did it
cost to drive 50 mph? 80 mph? ______________
Gallons
traveled, your car’s gasoline consumption increases as you increase
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
30 mph
50 mph
80 mph
Speed
2.
Suppose your car travels 45 miles at 50 mph
and uses 2 gallons of gas. How many miles per
gallon can it travel at this speed?______________
3.
At 80 mph your car will use 3 gallons of gas for
the same 45 miles. What is your car’s MPG at
this speed?
______________
4.
Mark’s car uses 4 gallons of gas to travel 120
miles at 30 mph. At 50 mph, the car uses 5
gallons of gas and at 80 mph, the amount of
gas used increases to 7 1_2 gallons. If gasoline
costs $1.60 per gallon, what is the total cost
of gasoline used at each speed?
MPH
Number of
Gallons Used
Total Cost of
Gasoline
Quick Reference
Gas-saving habits:
■ Avoid fast starts and stops. Drive at reduced
speeds.
■ When parked, turn off the engine. A car idling
for six minutes uses as much gasoline as driving
1 mile at 30 mph.
■ Keep your car in good running condition. Have it
checked regularly.
■ By driving sensibly and keeping your car in good
shape, you can save at least 15% on gasoline
costs.
Use the Quick Reference Box to answer questions 5 and 6.
On Your Own
Ask an automobile salesperson what effects these
additional accessories have on gasoline mileage:
A. An 8-cylinder rather than a 6-cylinder engine
B. air-conditioning,
C. automatic transmission,
D. power brakes, power steering, power doors and
windows.
5. On a trip to Toronto from New York, Mr. Johnson
drove through downtown Buffalo instead of taking
the bypass around it. Because of heavy traffic, his
car was stopped with the motor running for at least
12 minutes. Mr. Johnson wasted as much gasoline
as driving ________ miles at _________ mph.
6. Sandy Lightfoot figured out that by driving sensibly
and keeping her car in good shape, she reduced the
cost of driving her car by $.025 per mile. How much
savings is this if she drives 12,850 miles a year?
Real-Life Math © Scholastic Teaching Resources
69
Answer Key
Page 69
Gas-Saving Habits
1. a. 10
2. 22.5
3. 15
4. MPH
b.15
Number of
Gallons Used
Total Cost of
Gasoline
30
4
$6.40
50
5
$8.00
80
7.5
$12.00
5. 2, 30
6. $321.25
Real-Life Math © Scholastic Teaching Resources
104