When a car's tire pressure is 30 pounds per square inch (psi), it averages 20.5 mpg of gasoline. if the tire pressure is increased to 35 psi, the car averages 21.1 mpg of gasoline.
answer parts a) through c).
a) if someone drives an average of 23,000 mi per year, how many gallons of gasoline will he save in a year by increasing his tire pressure from 30 to 35 psi?

b.) if gasoline costs $2.00 per gallon, how much will he save in a year?

c.) assume that there are about 140million cars in a country and that these changes are typical of each car, how many gallons of gasoline would be saved if all drivers increased their cars' tire pressure?

For A, divide total miles by the miles per gallon for each tire pressure to find the number of gallons of gas used:

At 30 psi: 23000 / 20.5 = 1121.95 gallons , round to 1121 gallons.

At 35 psi: 23000 / 21.1 = 1090 gallons.

Number of gallons saved: 1121 - 1090 = 31 gallons.

B) multiply the cost per gallon by the number of gallons saved:

31 gallons x $2.00 = $62.00 saved.

C) Multiply the gallons saved by 1 car by total number of cars:

31 gallons x 140 million cars = 4,340 million gallons ( 4 billion 340 million gallons)

6 hours 48 min

step-by-step explanation:

68÷5=13.6

13.6×30=408min=6 hours 48 min.

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step-by-step explanation:

(3rd option) - c