Jim can fill a pool carrying bucks 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?
can u tell me how to do it and the answer
2007-05-16 20:02:38 · 4 answers · asked by candy c 1 in Science & Mathematics ➔ Mathematics
Let us assume that they can do it in x minutes when working together
therefore,
x/30 +x/45 +x/90=1(The complete work)
=>3x+2x+x=90(multiplying all by 90)
=>6x=90
=>x=15
Therefore they can do the work in 15 minutes
2007-05-16 22:12:30 · answer #1 · answered by alpha 7 · 0⤊ 0⤋
Jim = 30 minutes
Sue = 45 minutes
Tony = 90 minutes
Jim can do 1/30 of the work in a minute
Sue can do 1/45 of the work in a minute
Tony can do 1/90 of the work in a minute
Together, they complete (1/30 + 1/45 + 1/90) work in a minute.
1/30 + 1/45 + 1/90 = 5/90
= 1/15
They can together do 1/15 of the work in a minute.
So, they can complete the work together in 15 minutes.
2007-05-17 04:04:21 · answer #2 · answered by Akilesh - Internet Undertaker 7 · 0⤊ 0⤋
Jim can fill the pool in 30 min , Sue can fill the pool in 45min.,Tony can fill the pool in 90 min.,
Now find their i minute work ,
Jim = 1/30 , Sue =1/45 ,Tony = 1/90
Now find their combined i minute work = 1/30 + 1/45 + 1/90
= (3+2+1)/90 = 1/15
Now reciprocate it ,
So together they can do it in 15 minutes
2007-05-17 03:11:50 · answer #3 · answered by ritesh s 2 · 0⤊ 0⤋
All three working together can do it in 15 minutes.
2007-05-17 21:42:38 · answer #4 · answered by hack_ace 4 · 0⤊ 0⤋