SOLUTION: You pull out the plug from the bathtub. After 40 seconds, there are 13 gallons of water left in the bathtub. After one minute, there are 10 gallons of water left in the bathtub. Wh

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: You pull out the plug from the bathtub. After 40 seconds, there are 13 gallons of water left in the bathtub. After one minute, there are 10 gallons of water left in the bathtub. Wh      Log On


   



Question 866853: You pull out the plug from the bathtub. After 40 seconds, there are 13 gallons of water left in the bathtub. After one minute, there are 10 gallons of water left in the bathtub. Which equation correctly expresses the number of gallons left (g) in the tub in terms of the number of seconds since you pulled the plug (s)?
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
The description gives two ordered pair, and the rate of change between them is assumed as a constant. If (x,y) represents time since pull of plug and gallons of water in the tank, in that order, then your two points are (40,13) and (60,10). Find the line which contains these two points.

Using slope intercept form and the point (60,10),
b=y-mx;
b=10-%28%2813-10%29%2F%2840-60%29%2960=10-%28-3%2F20%2960=10%2B3%2A3=19
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highlight%28y=-%283%2F20%29x%2B19%29
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This bathtub hold 19 gallons as capacity.