90 - x = 4x
4x + x = 90
5x = 90
x = 90/5
x = 18
Square root of 36 to the third power is : 216
For this case the density is given by:
D = fish / volume
By clearing the volume we have:
volume = fish / D
Substituting values:
volume = (8) / (0.2)
volume = 40 feet ^ 3
Answer:
the volume of the tank is:
40 ft3
