Answer:
equation: y = 12x
Dr. Betz worked for 8 hours.
Step-by-step explanation:
To write the equation we'll use the form y = mx, where y represents the amount of time the Doctor worked, m is the amount of minutes it takes to treat each animal, and x is how many animals have been treated. We know the value of m is 12, so let's put that into the equation:
y = 12x
Now we have our equation. We can use it to see how long Dr. Betz worked. He treated a total of 40 animals - 20 including the shaggy dog, and 20 after the shaggy dog. let's replace x with 40:
y = 12(40)
Now solve:
y = 480
Dr. Betz worked for 480 minutes. There are 60 minutes in an hour. Divide 480 by 60 to find out how many hours Dr. Betz worked for:
480/60 = 8
Dr. Betz worked for 8 hours.