Posted by Dezy on Tuesday, December 2, 2008 at 10:08pm.
A log is cut into 4 pieces in 12 seconds. At the same rate how long would it take to cut the log into 5 pieces?
HINT: the answer is not 15

math  DrBob222, Tuesday, December 2, 2008 at 10:21pm
We make 3 cuts to get 4 pieces.
We must make 4 cuts to get 5 pieces.
Set up a proportion.
(3cuts/12 s) = (4 cuts/? s)
Cross multiply
3cuts * ?seconds = 48
? sec = 48/3 = 16 seconds.
Check my thinking. Check my work. 
math  Ms. Sue, Tuesday, December 2, 2008 at 10:23pm
To cut the log into 4 pieces takes 3 cuts. Each cut averages 4 seconds.
To cut the log into 5 pieces takes 4 cuts. How long do you think it will take to make 4 cuts?