# SOLUTION: If a contractor charges 30 for 2hours work and charges 94 for 4 hours of work what would he charge for 8 hours of work?

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 Click here to see ALL problems on Rational-functions Question 57649: If a contractor charges 30 for 2hours work and charges 94 for 4 hours of work what would he charge for 8 hours of work? Answer by tutorcecilia(2152)   (Show Source): You can put this solution on YOUR website!Since the amount of money charged increases with the amount of time spent working, there is a linear relationship between time and money. One type of equation you could use is the slope-intercept equation of a line (y=mx+b) . First find the slope of the line by using the two points that are given: (2, 30) and (4, 94) . Slope =m=(y-y2)/(x-x2) [Formula for the slope of a line] . m=(94-30)/(4-2)=64/2=32 [Plug-in the values of the two points] . y=mx+b 30=(32)(2)+b [Plug-in the values for the slope and one point] 30=65+b [Solve for b] -65+30=b -34=b . y=mx+b [Plug-in the values for the slope and the y-intercept (b)] y=32x-34 [Equation of the line] . To find any point on the line, plug-in the known variable and solve for the unknown variable: . Find (8, y) y=(32)(8)-34 y=222 So, when 8 hours are worked, the charge is \$222