Jim can fill a pool carrying buckets of water in 30 minutes. Sue can do the same job in 45 minutes. Tony can do the same job in 1 ½ hours. How quickly can all three fill the pool together?

Question

anonymous · Answer

Jim can fill a pool carrying buckets of water in 30 minutes. Sue can do the same job in 45 minutes. Tony can do the same job in 1 ½ hours. How quickly can all three fill the pool together?

anonymous · Answer

please help me to solve this one

saifoo.khan · Answer

trying..

anonymous · Answer

The trick to these is to reverse the way you look at them.

Tony can fill 2 pools in 3 hours.  Sue can fill 4 pools in 3 hours, and Jim can fill 6 pools in 3 hours.

(I used 3 hours so that they all work out to whole numbers)

So, combined, they can fille 12 pools in 3 hours...or 4 pools per hour.
This is the same a 1 pool in 15 minutes.

amistre64 · Answer

J does 1/30 in 1 min
S does 1/45 in 1 min
T does 1/90 in 1 min

add them all up

amistre64 · Answer

3/90
2/90
1/90
-----
6/90  ; flip it to get   90/6 minutes

anonymous · Answer

i don't understand dear

anonymous · Answer

mine, or amistre's?

amistre64 · Answer

lets assume it takes you 5 minutes to walk 1 mile; how many miles do you walk in 1 minute?

anonymous · Answer

12

amistre64 · Answer

1/5 of a mile in 1 minute, "plus"
1/5 of a mile in 1 minute, "plus"
1/5 of a mile in 1 minute, "plus"
1/5 of a mile in 1 minute, "plus"
1/5 of a mile in 1 minute, "plus"
---------------------------
5/5 of a mile in 5 minutes .... right?

anonymous · Answer

ok

amistre64 · Answer

in other words; you figure out how much work is down in "one" interval

if it takes J 30 minutes to do the whole job; how much is done in 1 minute?

anonymous · Answer

1/30

amistre64 · Answer

good; now lets do the same for S, it takes her 45 minutes to do the job, how much is done in 1 minute by her?

anonymous · Answer

1/45

amistre64 · Answer

excellent; now if we add their contributions together, we get the total amount of work done in 1 minute if they work together right?

anonymous · Answer

so what is equation for this ?

anonymous · Answer

1/30+1/45+1+90=?

amistre64 · Answer

1/J + 1/S + 1/T = total amount of work done by J+S+T in 1 minute right?

anonymous · Answer

yes

amistre64 · Answer

since and hour and a half equals 90 minutes, we get them all working in minutes ..

amistre64 · Answer

1/30 = J
1/45 = S
1/90 = T
--------
6/90  total ; remember how to add fractions

amistre64 · Answer

since the whole pool divided into 90 parts and 6 parts are filled each minute if they work together...

6*t = 90

t = 90/6