Start by finding the initial amount of water there was in the tub.
If it took 8 minutes to drain and it loose 62.5 liters per minute we can find the inital amount.
[tex](\frac{62.5L}{\min})\cdot(8\min )=500L[/tex]
continue by drawing a line between points (0,500) and (8,0)
using this line we can see how the water is being drained in the y-axis over the time in the x-axis.
