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Should you consider fuel efficiency, measured in miles per gallon, when buying a new car?
Suppose that car A costs $16,000 and gets 25 mi/gal, whereas car B costs $26,000 but gets 35 mi/gal.
Further, assume that the price of gasoline is $4/gal and that you plan to drive the car for (m) mi.
Taking into account price and fuel efficiency only,
(a) Write an expression CA for the cost of car A.
(b) Write an expression CB for the cost of car B.
(c) How many total miles m would you have to drive so that the cost is the same for both cars?
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(a) CA = 16000 + dollars. (Notice that is the number of gallons of fuel in this case,
and represents the cost of fuel for m miles)
(b) CB = 26000 + dollars. (Notice that is the number of gallons of fuel in this case
and represents the cost of fuel for m miles)
(c) CA = CB when
16000 + = 26000 + .
To find m from this equation, simplify it step by step
- = 26000 - 16000
- = 10000/4 = 2500
35m - 25m = 2500*25*35
10m = 2187500
m = 218750 miles. ANSWER
Solved.