Answer:
112.5 cubic meters
Step-by-step explanation:
Since area is same and depth only changes, we can find the ratio and multiply the volume by that.
depth of 8 meters is full (volume at 300 cubic meters), so when depth is 3 meters, the volume would be [tex]\frac{3}{8}[/tex] of 300, so:
[tex]\frac{3}{8}*300=112.5[/tex] cubic meters