SOLUTION: there are 3 pumps that fill a pool the first pump can fill the pool in 3 hours the second pump can fill the pull in 4 hours and the 3rd pump can fill the pool in 6 hours how long w

Question 961681: there are 3 pumps that fill a pool the first pump can fill the pool in 3 hours the second pump can fill the pull in 4 hours and the 3rd pump can fill the pool in 6 hours how long would it take to fill the pool if all 3 pumps are running at the same time
Answer by addingup(3677) (Show Source): You can put this solution on YOUR website!
To compare apples with apples, first you have to bring them to a common number. We'll make them all 1 hour. The first take 3 hours, so in 1 hour it fills 1/3 of the pool. The second takes 4 hours, so in 1 hour it fills 1/4 of the pool. And the last is 1/6. Working together, add them up:
1/3x+1/4x+1/6x = 1 Multiply all sides by 12 in order to have 1 as a denominator:
4x+3x+2x= 12
9x= 12
x= 12/9 divide both by 3:
x= 4/3 = 1 1/3 It takes the three pumps working together 1 1/3 hours to fill the pool. An hour has 60 minutes, so 1/3 is 20. Thus, it takes the three pumps 1 hour and 20 minutes to fill the pool.

RELATED QUESTIONS
A pump can fill a pool in 12 hours, and a second pump can fill the same pool in 6 hours.... (answered by macston)

If one pump can fill a pool in 16 hours and if two pumps can fill the pool in 6 hours,... (answered by Edwin McCravy)

One pump can fill a pool in 10 hr. Working with a second slower pump, the two pumps... (answered by nathany1280,josgarithmetic)

One pump can fill a pool in 16 hr. Working with a second slower pump, the pumps together... (answered by josgarithmetic)

Pump A, working alone, can fill a swimming pool in 6 hours. EIther one of pumps B or C,... (answered by josmiceli)

One pump can fill a swimming pool in 8 hours and another pump can fill it in 10 hours. If (answered by rothauserc,ikleyn)

two pumps working together can fill a tank in 2 hours. working alone the first pump can... (answered by fractalier)

Working alone, pump A can fill a pool in 8 hours, while pump B can fill it in 10 hours.... (answered by nerdybill)

one large pump can fill a swimming pool in 7 hours. a smaller pump takes 9 hours to fill... (answered by ikleyn)