### Instruction: An aquarium has a rectangular base that measures 100 cm by 40 cm and has a height of 50 cm. The aquarium is filled with water to a depth of 37 cm. A rock with volume $1000 \text{cm}^3$ is then placed in the aquarium and completely submerged. By how many centimeters does the water level rise?  Express your answer as a decimal to the nearest 100th.### Response: I need to find the change in water level, which is the same as the change in water volume divided by the area of the base.
The change in water volume is equal to the volume of the rock, since the rock displaces that much water when it is submerged.
So the change in water volume is $1000 \text{cm}^3$.
The area of the base is $100 \times 40 = 4000 \text{cm}^2$.
So the change in water level is $\frac{1000}{4000} = 0.25 \text{cm}$.
To express this as a decimal to the nearest 100th, I just need to round 0.25 to two decimal places, which is easy since it already has two decimal places.
So the final answer is 0.25.