Question

A water tank, having the shape of a rectangular prism of base 100 square centimeters, is being filled at the rate of 1 liter per minute. Find the rate at which the height of the water in the water tank increases. Express your answer in centimeters per minute.

Answer 1

The volume of a rectangular prism is given by 
area of base × height 
The rate at which the tank is being filled is 1 liter per minute which we need to convert 
1 liter = 1 dm³
But 1 dm = 10 cm. Hence 
1 liter = (10 cm)³ = 1000 cm³
The height h of the water is related to the volume by 
volume = area of base × h 
In one minute the volume increases by 1 liter or 1000 cm³ and the height increases by 
h = volume / area of base = 1000 cm³ / 100 cm² = 10 cm