SOLUTION: A log is cut into 4 pieces in 12 seconds. How long would it take to cut the same log into 5 pieces. The answer is not 15.

Question 105718: A log is cut into 4 pieces in 12 seconds. How long would it take to cut the same log into 5 pieces. The answer is not 15.
Found 2 solutions by bucky, fmo:
Answer by bucky(2189) (Show Source): You can put this solution on YOUR website!
Think about this ...
.
To cut a log into 4 pieces you need to make 3 cuts as follows:
.
xxxxx-cut-xxxxx-cut-xxxxx-cut-xxxxx
.
The strings of 5 x's represent the pieces. And the labels "-cut-" show where the cuts
are made. Therefore, with three cuts you create 4 pieces from the log. Since the total
time of the cuts is 12 seconds, the 3 cuts take 4 seconds each.
.
To cut the log into 5 pieces you need 4 cuts as follows:
.
xxxxx-cut-xxxxx-cut-xxxxx-cut-xxxxx-cut-xxxxx
.
Since each cut takes 4 seconds, the time for the 4 cuts is 4*4 = 16 seconds.
.
Hope this helps you to visualize the problem and see how to get the answer.
.

Answer by fmo(8) (Show Source): You can put this solution on YOUR website!
The pitfall here is in thinking that you need 4 cuts to make 4 pieces. You really need 3 cuts to make 4 pieces. Think about it, if you have one log and you make one cut, you know have two pieces of log. So, if you need to make 3 cuts and it takes you 12 seconds to do this, each cut takes:
12 seconds / 3 cuts = 4 seconds per cut
Now, to cut a similar log into 5 pieces would require 4 cuts at 3 seconds for each cut or:
4 cuts * 4 seconds/cut = 16 seconds.

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