I have an unmarked ruler (AD) of length 6cm. Making two marks in it, one (B) at 1cm from the left end and other (C) at 2cm from the right end, I´m able to measure any integer length from 1 to 6 cm:

       +----+-------------+--------+
       A    B             C        D

AB = 1cm / CD = 2cm / BC = 3cm / AC = 4cm / BD = 5cm / AD = 6cm.

If I have an unmarked ruler of length 14cm, what is the minimum number of marks, and where do I have to make them, in order to be able to measure any integer length from 1 to 14cm?

(In reply to 16 cm by monica)

Thus, "my method" gives a quick solution for any length, but not the optimal.

Ty.

Edited on November 16, 2008, 5:00 pm

Edited to remove "another 16cm". In fact it was "18"

Edited on November 17, 2008, 3:03 pm

Posted by pcbouhid on 2008-11-16 16:48:21