Linear equation

Question

A company can make 12 printing presses for $60,600. It can make 27 printing presses for $69,300. Find a linear equation that models the cost to produce x printing presses. Use slope-intercept form.

Answer 1

  Let m = slope = (cost of printing press)/(printing press)

 

1) $69,300  =  m*27 + b

 

2) $60,600  =  m*12 + b             Subtract 2) from 1)

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     $8,700   = m*15 + 0               Solve for m

 

 

   m = $8,700/15 = $580/printing press          Plug m into 1) or 2) and solve for b

 

b = 60,600 - m*15 = 60,600 - 580*15 = 51, 900    (or $51,900)

 

Therefore, y = $580*x + $51,900      where: y = total cost to produce printing presses

                                                                  x = number of printing presses produced