Re: [計量] 好多題計量請教
: 4. Two pipes can fill a tank in 10 hours and 12 hours respectively. A third
: pipe can drain the tank in 20 hours. How long will it take to be filed
: if all three pipes are open?
: ANS:7.5 hr
rate=1/10+1/12+1/20=(6+5+3)/60=7/30
=>30/7 不知道是不是我有誤解題目...
好像1/20 要用減的 drain 是流乾 所以用減的~ 算是來就是7.5
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推
02/10 00:27, , 1F
02/10 00:27, 1F
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02/10 00:28, , 2F
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02/10 00:28, , 3F
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02/10 00:30, 6F
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02/10 09:24, , 7F
02/10 09:24, 7F
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