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5-7

DRIVING DATA

Write, interpret, and use the distance formula.

Use the formula for the relationship between distance, fuel economy, and gas usage.

OBJECTIVES

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odometerelectronic odometermechanical odometertrip odometerspeedometerfuel economy

measurementmiles per gallon (mpg)kilometers per liter (km/L)

English Standard SystemMetric System

1 km ≈ 0.621371 mi1 mi ≈ 1.60934 km1 gal ≈ 3.8 L1 L ≈ 0.26 gal

distance formulaD = R × TD = mpg × galD = km/L × L

currency exchange rate

Key Terms

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Example 1Example 1

A car travels at an average rate of speed of 50 miles per hour for 6 hours. How far does this car travel?

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Example 2Example 2

Danielle drove from Atlanta, Georgia, to Denver, Colorado, which is a distance of 1,401 miles. If she averaged 58 miles per hour on her trip, how long is her driving time to the nearest minute?

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EXAMPLE 3EXAMPLE 3

Kate left Albany, New York, and traveled to Montreal, Quebec. The distance from Albany to the Canadian border is approximately 176 miles. The distance from the Canadian border to Montreal, Quebec, is approximately 65 kilometers. If the entire trip took about 3¾ hours, what was her average speed for the trip?

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EXAMPLE 4EXAMPLE 4

Juan has a hybrid car that averages 40 miles per gallon. His car has a 12-gallon tank. How far can he travel on one full tank of gas?

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EXAMPLE 5EXAMPLE 5

When Barbara uses her car for business, she must keep accurate records so that she will be reimbursed for her car expenses. When she started her trip, the odometer read 23,787.8. When she ended the trip it read 24,108.6. Barbara’s car gets 32 miles per gallon. Her tank was full at the beginning of the trip. When she filled the tank, it cost her $40.10. What price did she pay per gallon of gas on this fill-up?

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Suppose a person begins a trip with an odometer reading of A miles and ends the trip with an odometer reading of B miles. If the car gets C miles per gallon and the fill-up of gas for this trip cost D dollars, write an algebraic expression that represents the price per gallon.

CHECK YOUR UNDERSTANDING

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Example 6Example 6

David is driving in Mexico on his vacation. He notices that gas costs 8.50 Mexican pesos per liter. What is this equivalent to in U.S. dollars? (At David’s time of travel, 1 USD = 13.3 Mexican pesos.)

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Example 7Example 7

David knows that the price of gas in his home town is about $2.90 per gallon. How can he compare this price to the price paid in Example 6 for a liter?