Question 375952: A family has two cars. The first car has a fuel efficiency of 40 miles per gallon of gas and the second has a fuel efficiency of 30 miles per gallon of gas. During one particular week, the two cars went a combined total of 1650 miles, for a total gas consumption of 45 gallons. How many gallons were consumed by each of the two cars that week?
Found 2 solutions by stanbon, mananth:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A family has two cars. The first car has a fuel efficiency of 40 miles per gallon of gas and the second has a fuel efficiency of 30 miles per gallon of gas. During one particular week, the two cars went a combined total of 1650 miles, for a total gas consumption of 45 gallons. How many gallons were consumed by each of the two cars that week?
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Equation:
1st car DATA:
rate = 40 mi/gal ; # of gallons = x gal ; distance = 40x miles
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2nd car DATA:
30 mi/gal ; # of gallons = 45-x gal ; distance = 30(45-x) miles
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Equation:
40x + 30*45-30x = 1650
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10x = -1350+1650
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x = 30 gallons (gas consumed by 1st car)
45-x = 15 gallons (gas consumed by 2nd car)
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Cheers,
Stan H.
Answer by mananth(16946)  (Show Source):
You can put this solution on YOUR website! A family has two cars. The first car has a fuel efficiency of 40 miles per gallon of gas and the second has a fuel efficiency of 30 miles per gallon of gas. During one particular week, the two cars went a combined total of 1650 miles, for a total gas consumption of 45 gallons. How many gallons were consumed by each of the two cars that week?
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one car 40 miles /gallon
other car 30 miles/gallon
..
Total miles = 165
gas used = 45 gallons
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let first car drive x miles
second car drive y miles
..
x/40 + y/30 = 45
(30x+40y)/30*40 = 45
30x+40y = 45*40*30
30x+40y=54,000............................1
x+y = 1650...............................2
multiply (2) by -30
-30x-30y= 1650*-30
-30x-30y=-49,500
add to (1)
10y=4500
/10
y=450 miles
average = 30
consumption = 450/30
= 15 gallons
x= 1650-450=1200 miles
first car 1200/40 = 30 gallons
...
m.ananth@hotmail.ca
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