Another Word Problem

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troublemaker676

Junior Member
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Sep 1, 2005
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Hey guys just one more of these then i will have the test tomm. and will be done with them.

Auto companies advertise two rates for fuel mileage: City mileage is the rate of fuel consumption in stop and go traffic, and highway mileage is the rate of fuel consumption at higher speeds for longer periods of time. Cynthia's new car gets 17 miles per gallon in the city and 25 miles per gallon on the highway. She drove 220 miles on 11 gallons of gas. How many city miles and highway miles did she drive?

I defined may variables

x=highway miles
y=city miles

Now could someone help me determine the two equations that I need?

I got:

x+y=220

25x+17y=11 x 220

I don't think these are right though. Thanks for any help in advance. :D
 
Auto companies advertise two rates for fuel mileage: City mileage is the rate of fuel consumption in stop and go traffic, and highway mileage is the rate of fuel consumption at higher speeds for longer periods of time. Cynthia's new car gets 17 miles per gallon in the city and 25 miles per gallon on the highway. She drove 220 miles on 11 gallons of gas. How many city miles and highway miles did she drive?
I defined may variables
x=highway miles
y=city miles
Now could someone help me determine the two equations that I need?
I got: x+y=220 and 25x+17y=11 x 220
I don't think these are right though. Thanks for any help in advance.

Close- 25x + 17y = 11 and x + y = 220 will take you to your answer

Substitute y = 220 - x into 25x + 17y = 11 and you are home free.
 
When i substitute the equations:

25x+17(-x+220)=11

25x-17x+3740=11

8x+3740=11

8x=-3729

x=-466.125

Then i substitute that in for x in the other equation and get 686.125
Is this right?
 
You must have hypnotized Will.
x/25+y/17=11
is the correct equation.
Look at the units.
25x = 25 mi/gal*x miles = miles^2/gal but you say it equals gals.
x/25 = x miles/(25 miles/gal) =
gal*miles/miles = gals
That works.
 
x = gallons @ 25mph; so 11-x = gallons @ 17mph

25x + 17(11-x) = 220
25x + 187 - 17x = 220
8x = 33
x = 33/8 = 4 1/8

OK, tm?
 
Sure, if you're gonna change the variables... We got the same answer :roll:
 
Gene said:
Sure, if you're gonna change the variables... We got the same answer :roll:
Click to expand...
Ohhhh...only saw the poor guy was at "x=-466.125",
so thought it was time to give him close to the solution;
me no was trying to outdo anyone :shock:
 
Soorry troublemaker 676, I goofed and thanks to gene for catching the obvious.

x/25 + y/17 = 11 is the correct equation to use with x + y = 220.
 
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