A car travelled #213# miles on #14 2/10# gallon of gas. How many miles per gallon did it get?

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Answer 1 · 2018-05-05T12:21:47

#15# miles per gallon

To figure out how many miles per gallon the car got, divide the number of miles by the number of gallons:

#"miles" -:"gallons" = "miles per gallon"#

Now substitute the values given in the problem into that equation:

#213 -: 14 2/10 = "miles per gallon"#

Now turn #2/10# into a decimal. It would be #0.2#, so put #14color(blue).2# in:

#213 -: 14.2#

Use a calculator or long division to divide:

#213 -: 14.2 = 15#

So the car got #15# miles per gallon.

Answer 2 · 2018-05-08T09:35:48

The method used in the other two solutions would be based on this approach.

#color(blue)("For 1 gallon the miles travelled is 15.")#

The units of measurement required are

miles per gallon #->("miles")/("gallons")# so I am going to use this format. In other words; ratio in fraction format.

#("miles")/("gallons") -> 213/14.2#

But we need miles for 1 gallon so we need to change the #14.2# into 1. We do this by dividing it by itself.

For multiply or divide, what we do to the bottom we also do to the top.

#color(green)(("miles")/("gallons") -> 213/14.2 -> (color(red)(213-:14.2))/(14.2-:14.2) = color(red)(15)/1)#

Now you can see where the other methods come from: #color(red)(213-:14.2)#

#color(blue)("So for 1 gallon the miles travelled is 15.")#

In the UK this is a very high consumption and I would get rid of that car. Replacing it with a more economical one.