decrease cell based on incremental increase of adjacent cell

Question

Hi, 

The example I am trying to change is Miles Per Gallon (MPG), based on a vehicles MPH. So the if the MPH in one cell increases by 1, then the MPG in the adjacent cell decreases by .14 for every 1 increase in the MPH cell 

Answer 1

 

MPG is a function of MPH

 

y is MPG and x is MPH

 

y = f(x) ---> (x,y)

 

y-.14 = f(x+1) ---> (x+1, y-.14)

 

the slope is -0.14

 

 

Now all you need is a STARTING Point.

You need an ACTUAL point of data, an ordered pair, that

shows what is the MPG for a particular MPH.

 

Once you get it, plug it into the formula:

  B = MPG + 0.14 (MPH)   

 

The linear equation shall then be y = -0.14x + B

 

You will code the formula then in excel as

 

  =-0.14*CELL + B where hte MPH is in the input cell

and B is calculated above