A histogram titled, Volume of water Hurley drank each day, plots Number of days, versus Volume, in liters, from 0 to 6, in increments of 1. There is no bar between 0 and 1. Bar heights are approximately as follows. From 1 to 2, 4. From 2 to 3, 5. From 3 to 4, 8. From 4 to 5, 8. From 5 to 6, 6.
For how many days did Hurley measure the volume of water that he drank?
days