• Feb 26, 2007, 12:19 PM
kristo
2 maths exercises
1. A pipe fills a pool in 4 hours, another pipe drains a full pool in 6 hours. How long will it take to fill the pool if both pipes are opened?

2. A pool is connected with 3 pipes. Two pipes fill the pool and one drains it. It takes 3 hours for first pipe to fill the pool and 2 hours for the 2nd one. The third pipe drains a full pool in 6 hours. How long will it take to fill the pool if all pipes are opened?

Ugh, they seem so simple lol, but I can't solve them, just a few guidelines would help..
I'm off to sleep now, so thanks to anyone who helps.
• Feb 26, 2007, 12:25 PM
Capuchin
1) pipe 1 fills the pool 1/4 in 1 hour. Pipe 2 drains the pool 1/6 in 1 hour
you're looking for the condition:

$t(\frac{1}{4}-\frac{1}{6}) = 1$

solve for t

2) you can do the same for this one, have a go and tell me what you come up with.

Let me know if you need further help.
• Feb 27, 2007, 04:58 AM
kristo
Thanks!
So is it 12h for the first one and 1.5h for the 2nd exercise?
• Feb 27, 2007, 05:02 AM
Capuchin
That's what I got :)

Well done!

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