Answer:
The depth will be 4.1 ft
Explanation:
Here, we have a linear model to work with
Between 1:30 pm and 3:30 pm, there was a difference of 3.8-2.6 = 1.2 ft on the depth
What we can see there is that in 2 hours, there was a difference of 1.2 ft
So the filling rate per hour will be 1.2ft/2 hours = 0.6 ft/hr
Now, we want to know the depth of the water at 4:00 pm
The difference between 3:30 and 4 pm is 30 minutes = 0.5 h
so by addition;
3.8 ft + 0.5(0.6)
will give the depth of the water at 4 pm
That will be;
3.8 + 0.3 = 4.1 ft
We used 3.8 ft as it is the depth at 3:30 pm
Then we need to add what is topping this after 30 minutes of filling using the constant filling rate and the time