Yahoo Answers: Answers and Comments for One pipe can fill a tank in four hours; another pipe can fill the same tank in three hours.? [Mathematics]
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From Anonymous
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Wed, 22 May 2019 08:58:14 +0000
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Yahoo Answers: Answers and Comments for One pipe can fill a tank in four hours; another pipe can fill the same tank in three hours.? [Mathematics]
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https://answers.yahoo.com/question/index?qid=20190522085814AAVbzHz
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From 冷眼旁觀: Let t hours be the time taken to fill the tank...
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Wed, 22 May 2019 09:05:36 +0000
Let t hours be the time taken to fill the tank if both pipes filled at the same time.
The first pipe fills 1/4 of the tank in one hour.
The second pipe fills 1/3 of the tank in one hour.
[(1/4) + (1/3)] × t = 1
[(3/12) + (4/12)] × t = 1
(7/12)t = 1
t = 12/7
t = 1_(5/7)
It takes 1_(5/7) hours.

From Φ² = Φ+1: The first pipe can fill 3 tanks in 12 hours, w...
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Wed, 22 May 2019 09:18:11 +0000
The first pipe can fill 3 tanks in 12 hours, while the second pipe can fill 4 tanks in 12 hours.
Together they can fill 7 tanks in 12 hours, which is 1 tank in 12/7 hours.

From Amy: Least common multiple of 3 and 4 is 12.
In 12...
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Wed, 22 May 2019 09:16:32 +0000
Least common multiple of 3 and 4 is 12.
In 12 hours, the first pipe can fill 3 tanks and the second pipe can fill 4 tanks.
Thus the two pipes together can fill 7 tanks in 12 hours.
Filling 1 tank takes 12/7 hours.

From Como: 
Let volume of tank be V m³
Rate for pipe 1 ...
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Wed, 22 May 2019 21:38:09 +0000

Let volume of tank be V m³
Rate for pipe 1 = V/4 m³/h
Rate for pipe 2 = V/3 m³/h
Combined rate = 7V/12 m³/h
Time to fill = V / ( 7V/12) = 12/7 = 1•7 hours = 1 h 42 min

From Mike G: t/4+t/3 = 1
7t = 12
t = 12/7 hours
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Wed, 22 May 2019 11:03:11 +0000
t/4+t/3 = 1
7t = 12
t = 12/7 hours

From Ian H: Add rates in terms of fraction of a tank per h...
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Wed, 22 May 2019 14:01:27 +0000
Add rates in terms of fraction of a tank per hour.
1/4 + 1/3 = 7/12 of a tank per hour, so takes 12/7 hours to fill 1 tank

From King Leo: .
¼ + ⅓ = 7/12
time = 1/ (7/12 ) = 12/7 hrs
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Wed, 22 May 2019 09:04:18 +0000
.
¼ + ⅓ = 7/12
time = 1/ (7/12 ) = 12/7 hrs

From david: Rate for 1st = 1/4 tank/hr
Rate for 2nd = 1/...
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Wed, 22 May 2019 09:22:04 +0000
Rate for 1st = 1/4 tank/hr
Rate for 2nd = 1/3 tank /hr
... mult. each by time to get how much it fills
... add to = 1 (need to fill 1 tank)
(1/4)t + (1/3)t = 1 >>> get common denom.
3t/12 + 4t/12 = 1
7t/12 = 1
t = 12/7 hours
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