algebra
posted by Shaunna .
How do you find year elapsed using miles per gallon??

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There is a graph and it is divided into 3 columns and the first one is the year and the middle one is the years elapsed and the 3rd one is miles per gallon....and the question is...calculate the years elapsed since 1960 to complete it. So I have to fill in the middle column and I have no idea how to find it!!