Answer:
The volume is decreasing at a rate 20π cubic meter per hour.
Step-by-step explanation:
We are given the following in the question:
The radius is increasing at a rate 1 meter per hour.
The height is decreasing at a rate 4 meter per hour

At an instant time t,
r = 5 meter
h = 8 meters
Volume of cylinder =

where r is the radius and h is the height of the cylinder.
Rate of change of volume is given by:

Putting all the values we get,

Thus, the volume is decreasing at a rate 20π cubic meter per hour or 62.8 cubic meter per hour.