Easy Algebra Problem - please help! (: ?

Question

Suppose you drive a car 392 mi on one tank of gas. The tank holds 14 gallons. The number of miles traveled varies driectly witht he number of gallons you use.

1) Last year you drove 11,700 mi. About how many gallons of gas did you use?

2) Suppose the price of gas averaged $1.57 per gallon last year. Find the cost per mile.

My work:

1) y=kx

1170/14=14x/14

x= 83.6 gallons

2) I'm completely stuck on - please, full explanation appreciated! (:

x

Answer 1

First firgue out your miles per gallon.

392miles on 14 gallons

392/14=28 miles per gallon

1) so to drive 11,700 miles devide by your MPG

11700/28=418gallons (I rounded up)

2) cost is the total gallons times the price

418*1.57=$656.26

Answer 2

Your car can hold 14 gallons of gas.  Multiply 14 by $1.57.  This is how much one tank of gas will cost you.  Now, divide the cost for the entire tank of gas by 392 miles, which is the number of miles you can drive on one tank of gas.  This will give you the answer you need.  However, don't ever assume that your car can drive exactly that far on one tank - there may not be a gas station at the end of the tank.  Buy gas before you run out completely.  = )

Answer 3

okay so you know you get 28 miles per gallon right?

which means driving 28 miles costs you 1.57.***

So divide 1170 by 28 and that's how many gallons you'll use then multiply that number by 1.57. :)!!

***28mi for 1gallon; 1.57 for for 1 gallon, use transitive property (if a=b & a=c then b=c) so 28 miles for 1.57

Answer 4

put x into the first equation

Answer 5

392/14=28  28 miles per gallon

11,700/28=417.857 gallons

417.857*1.57=$656.03

656.03/11,700=.056  round off to $.05 per mile

Answer 6

1.   392 mi/14 gal = 11,700 mi/ x gal

      (14 * 11,700) / 392 = 417.85 gallons used last year.

2.   $1.57 / 1 gal = $x / 417.85 gallons

      ($1.57 * 417.85 gal) / 1 gal = $656.02

All you have to do is set up the proportions, cross multiply, and then solve for the unknown variable (x).

Answer 7

392/14=28 miles per gallon so,

1)  11,700 miles / 28 mpg = 417.85 approximate gallons used to travel

2)  Average price per gallon of $1.57 multiplied by the number of gallons of 417.85 says you spent approximately $656.03

Hope this helps.

Answer 8

1) For every 392m you drive, you use 14g. So your equation would be:

11,700m/392m × 14g = x

x = 417.86 gallons of gas

2) How many miles do you drive per gallon? The equation would be:

392m/14g = 28m/g

The cost per gallon of gas is $1.57 so:

($1.57/g) / (28m/g) = x

$1.57/28m = $0.056/m

Answer 9

divide $1.57 by (miles per gallon) then multiply that by how many miles driven.