Determine whether quantities vary directly or inversely and find the constant of variation. it takes three identical water pumps 8 hours to fill a pool. how long would it take four of these same pumps to fill the pool, assuming they all pump at the same rate?

8 * 3 = 24
24/4 = 6 HOURS

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.