Two large and 1 small pumps can fill a swimming pool in 4 hours. One large and 3 small pumps can also fill the same swimming pool in 4 hours. How many hours will it take 4 large and 4 small pumps to fill the swimming pool?(We assume that all large pumps are similar and all small pumps are also similar.)

PsychoBaker
Jul 13, 2017

#1**0 **

2L + s =L + 3s, solve for L

L =2s One large pump is equivalent to 2 small ones.

Since (2Lx2)+ s = 5 small pumps can fill the pool in 4 hours, therefore:

[4Lx2]s + 4s =12 small pumps can fill the pool in:

4 / [12/5] =4 x 5/12=20/12 =1 2/3 hours - or 1 hour and 40 minutes.

Guest Jul 13, 2017

edited by
Guest
Jul 13, 2017

#1**0 **

Best Answer

2L + s =L + 3s, solve for L

L =2s One large pump is equivalent to 2 small ones.

Since (2Lx2)+ s = 5 small pumps can fill the pool in 4 hours, therefore:

[4Lx2]s + 4s =12 small pumps can fill the pool in:

4 / [12/5] =4 x 5/12=20/12 =1 2/3 hours - or 1 hour and 40 minutes.

Guest Jul 13, 2017

edited by
Guest
Jul 13, 2017