You have to boil a single egg for exactly nine minutes.
All you have are two hourglasses, able to measure (in sand) seven and four minutes, respectively.
How quickly, using only these two hourglasses, can you boil an egg?
(In reply to
try.. by Cheradenine)
Your answer is a little too abstract, and it was hard to follow exactly what you were saying, but if I've interpreted it correctly, I believe that it is correct:
Start the egg and both timers (t = 0,T4 will run out in 4 minutes, T7 will run out in 7 minutes)
when the 4 minute timer runs out, turn it over (t = 4, T4 = 4, T7 = 3)
When the 7 minute timer runs out, turn it over (t = 7, T4 = 1, T7 = 7)
When the four minute timer runs out turn over the 7 minute timer (t = 8, T4 = 0, T7 = 1)
When the 7 minute timer runs out, the egg is ready. (t = 9, T4 = 0, T7 = 0)
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Posted by TomM
on 2002-07-05 12:51:08 |
re: try..
