A tank was filled with 160 ℓ of water at 12 00. Water flowed out of the tank from 12 00 to 16 00. The line graph shows the amount of water in the tank from 12 00 to 16 00. Which one-hour period shows the most increase in the amount of water in the tank? Give your answer in this format. (Eg 12 00 to 13 00)


To find the most increase in a line graph, look for a decreasing slope that is the steepest. This indicates that the most decrease in the amount of water in the tank.

To prove:

Between 12 00 and 13 00:
Volume of water that flowed out
= 160 - 115
= 45 ℓ

Between 13 00 and 14 00:
Volume of water that flowed out
= 115 - 90
= 25 ℓ

Between 14 00 and 15 00:
Volume of water that flowed out
= 90 - 55
= 35 ℓ

Between 15 00 and 16 00:
Volume of water that flowed out
= 55 - 5
= 50 ℓ

One-hour period that shows the most decrease in the volume of water = 15 00 to 16 00 

Answer(s): 15 00 to 16 00