Answer: 0 ≤ y ≤ 70 and 0 ≤ x ≤ 500
Step-by-step explanation:
In this relation we have two things to analyze, the number of gallons of water in the heater, that is 500 gallons, and the time that it took to empty the heater.
Let's count the time.
First, there are 20 minutes in wich 100 gallons are drained.
then, another drain valve is opened, so in 20 minutes they drain 200 gallons of water.
now, the wait for 10 minutes.
Now there are 200 gallons remaining, so the workers must wait for the other 20 minutes to drain the 200 gallons remaining.
The total amount of time is 70 minutes.
So if we have a relationship of water in the heater vs time, where X is the water remaining and Y is the time, the correct domains are:
Y from 0 minutes to 70 minutes
X from 0 gallons to 500 gallons
So the correct options are C and E.
0 ≤ y ≤ 70 and 0 ≤ x ≤ 500