SOLUTION: Suppose that the distance a car travels varies directly with the amount of gasoline it uses. A certain car uses 9 gallons of gasoline to travel 207 miles. How many miles can the ca
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Question 1202518: Suppose that the distance a car travels varies directly with the amount of gasoline it uses. A certain car uses 9 gallons of gasoline to travel 207 miles. How many miles can the car travel if it has 13 gallons of gasoline? Found 3 solutions by mananth, josgarithmetic, greenestamps:Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website!
distance a car travels varies directly with the amount of gasoline it uses.
dg
d=kg
car uses 9 gallons of gasoline to travel 207 miles
207 = 9k
k= 23
. How many miles can the car travel if it has 13
d = 23*13 =299 miles
Informal way
9 gallons 207
13 gallons ?
You can put this solution on YOUR website! ----------------------------------------------------------
the distance a car travels varies directly with the amount of gasoline it uses.
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The language clearly becomes, with these assigned variables,
k, variation constant
d, distance travel
x, amount of fuel used
;
the equation .
The part which follows in the description is that x=9 corresponds to d=207; so you can find the value for k.
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Notice the units for each number involved in the question.
13 gallons of gasoline;
9 gallons gasoline for 207 miles;
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Question is "how many miles travel if 13 gallons...?"
Begin with the 13 gallons:
If you need to find the exact formula, to be used repeatedly, relating distance and gallons of gas, then you want to find the constant of proportionality, as shown in the responses from the other tutors.
However, if you are only required to solve this particular problem, doing the work to find that constant is extra unnecessary effort.
Since the variation is direct, the factor by which the distance changes will be the same as the factor by which the number of gallons of gas changes. So the answer is the result of a single simple calculation:
(