Problem-Solving:
Figuring Out Miles Per Gallon
Today's snack: Have some popcorn. How much? Well, not a
gallon in one sitting. Figure it out: if there are eight ounces in a cup, and
16 cups in a gallon, how many ounces of popcorn would make one gallon? (Answer:
8 x 16 = _______) Whoa! That's too much to eat in one day. But you could
probably eat a whole gallon of air-popped, butter-free popcorn in one week, and
feel great!
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Supplies:
Scratch paper and pencil
Do you know how to figure out how many miles per
gallon of gas a car gets? You look in the owner's manual to see how many
gallons of gas the car's tank holds. Then you fill it up with gas, and write
down the mileage from the odometer.
Next time you fill 'er up with gas, you write down
how many gallons the tank took. With that information, you can compute how many
miles you drove, and how much gas you used.
All you do is subtract the old
mileage from the new mileage, and divided that by the number of gallons you
just put in your car.
Let's say the last time you got gas,
you had 20,175 miles on the odometer. You put in 10 gallons of gas 'til your
tank was full. This time, you had 20,325 miles on the odometer, and you filled
it up again.
20,325
-
20,175
150
(So: miles driven on 10
gallons of gas = 150 ÷ 10 = 15 miles per gallon of gas)
You could put a small notebook in
your car's glove box, and every time your family gets gas, the total gallons
and price should be recorded. Also write down whether you were mostly driving
around doing errands on the city, or count up your highway miles; cars are
generally more gas-efficient when they're driven steadily at a pretty fast
speed without a lot of starting and stopping.
Then once a month or so, you can look at the numbers
with a grownup, and figure out what your gas mileage is.
Another example:
Let's say your vehicle's tank holds 20 gallons and
the odometer shows 10,000 miles. Next time you get gas, your vehicle takes in
six new gallons to get to "F" for full. Your odometer shows 10,120 miles. Subtract
the 10,000 miles you started with from the 10,120 miles it shows now. That
means you went 120 miles on six gallons of gas. Divide the 120 by 6, and you'll
come up with 20. That means you got 20 miles per gallon. Not great. But not
bad!
The miles per gallon will differ
significantly with the type of vehicle that's being used, how fast it goes, how
much it weighs, and what type of movement it's making. For example, a Formula 1
racing car gets just over 3 miles per gallon - significantly less than your
family car, no doubt:
http://wiki.answers.com/Q/How_many_miles_per_gallon_does_a_Formula_1_car_get
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Now use your math skills
to figure out how many miles per gallon
each of these
vehicles gets!
MULTIPLICATION
CHALLENGE:
MILES PER
GALLON
Motor scooter: 80
miles per gallon
How far could you go on 3.75 gallons
of gas? (80 x 3.75 = __________ miles)
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Two-door sports car:
29 miles per gallon (highway)
How far could you go on 19.2 gallons
of gas? (29 x 19.2 = _________ miles)
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Monster truck: 7 miles
per gallon
How far could you go on 53.8 gallons
of gas? (53.8 x 7 = ________ miles)
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Speed boat: 6 miles
per gallon
How far could you go on 14.6 gallons
of gas? (14.6 x 6 = ________ miles)
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Commercial airliner: 5
miles per gallon
If the maximum distance this plane
can fly is 3,500 miles, how much fuel would that take?
(5 x 3,500 = ___________ gallons)
