In the table shown below:
Let N be the number of bottles filled,
Let T be the time in hours.
Given that the number of bottles filled is proportional to the amount of time the machine runs, we have
Let's evaluate the value of k for each day.
Thus, on monday,
Tuesday:
Wednesday:
Thursday:
It is observed that all exept wednesday have the same value of k.
Thus, the amount of time required for the number of bottles filled on wednesday is evaluated as
Hence, the incorrect day is Wednesday. The amount of time for that many bottles should be 6.85 hours.
You find the area by multiplying all