Answer:
a. 509 m³
Explanation:
a. Assume that the silos are cylinders with a circular base. The volume of a silo is given by:

If the radius (r) is 3 meters, and the height (h) is 18 meters, the volume is:

Total volume is 509 m³
b. If the flow rate is 1 m³ per 3 minutes, the time required to fill the whole 509 m³ is:

It will take 25.45 or roughly 25.5 h to fill one of these silos.