label Mathematics
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car 1 uses 35mpg, car 2 uses 20mpg. in 1 week cars traveled combined total of 1125 mls. using 45 gallons of gas. How many gallons for car 1? car 2?

Oct 27th, 2015

I am going to use two equations. One will be for the amount of miles car 1 and car 2 go and the other will be for the amount of gas they use.

Miles equation:

35x+20y=1125 where x=gallons car 1 uses and y=gallons car 2 uses.

Gallons of gas equation:

x+y=45 where x and y are the same as in the Miles equation.

x=45-y I just rearranged the equation above and will substitute it into the Miles equation.

35(45-y)+20y=1125

1575-35y+20y=1125 I distributed the 35 across the parantheses.

1575-15y=1125 I combined like terms. Now subtract 1575 from both sides.

-15y=-450 Divide both sides by -15

y=30

x=45-y=45-30=15

car 1 uses 15 gallons and car 2 uses 30 gallons.

Oct 27th, 2015

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Oct 27th, 2015
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Oct 27th, 2015
Sep 24th, 2017
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