Burning Metal Riddle?

  • Thread starter Thread starter Rathe
  • Start date Start date
R

Rathe

Guest
Some scientists have discovered a new form of metal which is bout three inches long. this metal burns for exactly half an hour. However it burns oddly, two inches of it might burn in one minute and the last inch may take 29 minutes to burn. By burning two of the stick of metal how can you tell when 45 minutes has passed?
 
Given:

1 stick (3 inches) = burns for 30 mins.

first 2 inches of the stick = burns for 1 min.
remaining 1 inch of the stick = burns for 29 mins.

Asked:

Measurement of the stick upon 45 mins. of burning.


Solution:

Assuming that we will burn 2 metal sticks continuously.

1st stick (3 inches) = 30 mins.

2nd stick
first 2 inches = 1min.

(from here we already have 31 mins.
45 - 31 = 14 ; we need to measure 14 mins for the remaining inch.
since the remaining 1 inch of the 2nd stick burns for 29 mins. we can arrive at a ratio of 1min = 1/29 inch, therefore)

remaining 14/29 inch = 14 mins.

Therefore, we need to burn the whole 1st stick (that is 3 inches) and 2 14/29 inches for the 2nd stick.

also, I would just use my watch

:- P
 
Back
Top