Question

A rain barrel is full of water and used to water the garden. The rain barrel loses water at the rate 2.5 gallons of water per minute. After seven minutes, the rain barrel contains 37.5 gallons.
Write an equation in point-slope form to model the number of gallons (y) of water in the rain barrel after (x) minutes. Show or Explain your work.

Answer 1

Answer: y - 37.5 = 2.5 ( x - 7)

Explanation:

1) The point-slope form is has this form:

 y - y1 = m (x - x1)

Where m is the slope or rate of change and x1, y1 are the coordinates of the point.

2) you are told that the the rate of change of water (m) is 2.5

m = 2.5

3) The point is given by that after 7 min the rain barrel contains 37.5 gallons. This is:

x1 = 7
y1 = 37.5

4) Replace those value in the point-slope model:

y - 37.5 = 2.5 ( x - 7)

That is the point-slope model or equation.