Barbara turns on her water to begin filling a tub. After pouring water into the tub at a constant rate for 5 minutes, Barbara turns off the water for 15 minutes. Then Barbara unplugs the tub to allow the water to begin draining out. The water drains at a constant rate for 20 minutes until the tub is empty again.

Which graph represents the volume of water in the tub during this time?

1 answer

To represent the scenario you described graphically, we'll break it down into three distinct phases:

  1. Filling Phase (0 to 5 minutes):

    • During the first 5 minutes, the water is filling up the tub at a constant rate. This would show a linear increase in volume on the graph.
  2. Paused Phase (5 to 20 minutes):

    • After 5 minutes, Barbara turns off the water for 15 minutes. During this time, the volume of water remains constant. On the graph, this would be represented as a horizontal line for 15 minutes (from 5 to 20 minutes).
  3. Draining Phase (20 to 40 minutes):

    • After 20 minutes, the water begins to drain at a constant rate for 20 minutes. This will be represented as a linear decrease in volume on the graph. The graph would slope downward during this period.

Putting this all together, the graph would:

  • Start at a point (let's say it begins at 0 volume at 0 minutes).
  • Show a linear rise from 0 to some peak volume over the first 5 minutes.
  • Show a flat horizontal line at that peak volume from 5 to 20 minutes.
  • Show a linear decline from the peak volume back to 0 over the final 20 minutes.

In summary, the graph would have:

  • An initial linear increase,
  • A flat section,
  • Followed by a linear decrease.

If you have specific graphs to choose from, look for one that matches this description.