It takes a large pipe 45 minutes to fill a pool. A smaller pipe can fill the pool in 110 minutes. Working together, how long does it take (to the nearest minute) for both pipes to fill the pool.

Question

It takes a large pipe 45 minutes to fill a pool.  A smaller pipe can fill the pool in 110 minutes. Working together, how long does it take (to the nearest minute) for both pipes to fill the pool.

amistre64 · Answer

how much of the pool is filled in 1 minute by each of them seperately?

amistre64 · Answer

Lp = 1/45 parts per minute

Sp = 1/110  parts per minute 

right?

amistre64 · Answer

Lp + Sp working together fill the what part in one minute?

1/45 + 1/110 = 155/4950  is my easy math way :)

amistre64 · Answer

155 parts out of 4950 are filled in 1 minute by both pipes working together

amistre64 · Answer

31/990 might be an easier fraction to play with...

anonymous · Answer

so if the question was in hours would i just find how much of "x" is completed in one hour?

amistre64 · Answer

Yep.... that would be it...then figure out how long it takes to do the entire "job"

amistre64 · Answer

31 minutes and  29/31 left to fill
     ------
31| 990
       93
      ----
         60
         31
        ----
         29

amistre64 · Answer

id say 32 minutes at most :)

anonymous · Answer

you lost me

anonymous · Answer

i got how we had 155/4950

anonymous · Answer

then we simplified?

amistre64 · Answer

if I did the addition right:  we get 155 parts out of 4950 that are being doen in one minute

155 divides 4950 how many time?

anonymous · Answer

31?

amistre64 · Answer

155 + 155 + 155 + 155....till you get near 4950

anonymous · Answer

OHHH

anonymous · Answer

ok i get it THANKS

amistre64 · Answer

155
    31
-----
  155
365
-----
4805   right?

anonymous · Answer

oh
 32

amistre64 · Answer

4950
-4805
------
    145  more parts to fill  out of 155 per minute :)

amistre64 · Answer

which is close to 1 minute so round to 32 :)

anonymous · Answer

instead of confusing yourself just think about it as if you were filling up your pool asnd you really wanted to go swim do you decide to use both of them so it can go faster one of you freinds asks you about what time will it be done and and you give her an amout of min. whatr would you tell him/her?

amistre64 · Answer

that last part always used to get me...  until I realized the the "155" took one full minute and we only needed "145" of those:

145
--- is the reminder of the minute which is close enough to 1 right :)
155

anonymous · Answer

ok that makes sense

anonymous · Answer

thanks :)

anonymous · Answer

who u talkin 2...

anonymous · Answer

not you

anonymous · Answer

i no but i want to know which person is right i am trying to figure it our myself and btw dnt be ruse witrh me u dnt know who u tlkkin to...