SOLUTION: The gas mileage, M, of a compact car is a linear function of the speed,s, at which the car is driven, for 40 <-s90<-(not sure how to get the line under the <). From the graph we se

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: The gas mileage, M, of a compact car is a linear function of the speed,s, at which the car is driven, for 40 <-s90<-(not sure how to get the line under the <). From the graph we se      Log On


   



Question 473706: The gas mileage, M, of a compact car is a linear function of the speed,s, at which the car is driven, for 40 <-s90<-(not sure how to get the line under the <). From the graph we see that the gas mileage for the compact car is 45 miles per gallwon if the car is driven at a speed of 40 mph and the gas mileage for the compact car is 20 miles per gallon if the car is friven at a speed of 90 mph. find the linear function M(s) in sleop intercept form. Interpret the slope found in a. Find and interpret M(60).
Answer by stanbon(75887) About Me  (Show Source):
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The gas mileage, M, of a compact car is a linear function of the speed,s, at which the car is driven, for 40 <-s90<-(not sure how to get the line under the <). From the graph we see that the gas mileage for the compact car is 45 miles per gallon if the car is driven at a speed of 40 mph and the gas mileage for the compact car is 20 miles per gallon if the car is driven at a speed of 90 mph. find the linear function M(s) in slope-intercept form. Interpret the slope found in a. Find and interpret M(60).
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You have 2 points relating mileage and speed: (40,45) and (90,20)
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slope = (20-45)/(90-40) = -25/50 = -1/2
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M = (slope)s + b
Solve for "b":
20 = (1/2)90 + b
20 = -45 + b
b = 65
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Equation:
M(s) = (-1/2)s + 65
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M(60) = (-1/2)*60 + 65
M(60) = -30 + 65
M960) = 35 mpg
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Cheers,
stan H.