(This is an old chestnut of a puzzle, but with a slight twist)
It takes six minutes for just the cold tap to fill my bath with water.
The hot tap fills the bath at the same rate, but unfortunately (due to some strange plumbing) after the hot tap has been running for three minutes its supply of water shuts off for a full two and a half while the hot water tank refills and reheats - after the two and a half minutes, the hot tap commences dispensing water once again.
With the plug pulled out, a full bath empties (at a uniform rate) in only four minutes.
With the hot water tank full and the plug pulled out, how long will it take my bath to fill if I turn both taps on?
(In reply to
Solution? by Dulanjana)
Your solution reminds me of the pitfall in the cattepillar problem:
The cattepilar si climbing up a 10 foot pole. it climbs 6 feet up during the day, but slides down 5 feet at night. When will it reach the top?
Some people immediately say 10 because they figure it's only moving 1 foot a day. But really, after four days, it will be four feet up, and on the fifth day will climb the remaining 6 feet before nightfall, thus reaching the top on the evening of the fifth day.
The work of the hot tap is not evenly distributed over its 5.5 minute cycle, so we can't just take its speed to be a uniform 1/5.5...
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Posted by levik
on 2002-07-03 05:01:37 |
re: Solution?
