SOLUTION: a barrel contains 168 gallons of water and is being drained at a constant rate of 13 gallons per day. What is the equation that models the number of gallons, g, after t days?
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Question 645493: a barrel contains 168 gallons of water and is being drained at a constant rate of 13 gallons per day. What is the equation that models the number of gallons, g, after t days? Answer by solver91311(24713) (Show Source):
At zero days, there are 168 gallons in the barrel, so a graph of your function on a coordinate plane where points are denoted with ordered pairs of the form , must have the point on it.
At one day, there are 168 minus 13 equals 155 gallons in the barrel, so the graph of your function must have the point on it.
Now that you have two points on a graph of your function, you can use the two point form of an equation of a line to model your function:
where and are the coordinates of the given points.
Just plug in the numbers and then do the arithmetic. Then arrange your equation so that your have by itself in the LHS.
John
My calculator said it, I believe it, that settles it
