Determine whether quantities vary directly or inversely and find the constant of variation.
It takes four identical water pumps 6 hours to fill a pool. How long would it take three of these same pumps to fill the pool, assuming they all pump at the same rate?
Time taken by 4 water pumps to fill the pool is 6 hours Time taken by 1 pump will be: 4×6=24 hours fraction of pool filled by a single pump in 1 hour will be: 1/24 To calculate how long it would take 3 pumps to fill the pool we proceed as follows: Fraction of pool filled with water in 1 hour is: 3×1/24 =1/8 thus the time taken to fill the pool by 3 pumps is: 8/1=8 hours
