2009 Grade 8 CEMC Gauss Problems/Problem 22
Problem
A dollar sign is formed by drawing two parallel vertical lines through the letter S, as shown. These lines cut the letter S into pieces. What is the minimum total number of parallel vertical lines that are needed to cut the letter S into exactly
pieces?
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Solution
We can see that the first line cuts the letter S into four pieces ( pieces to the left of the line, and
pieces to the right), and that each additional line adds
more pieces.
This means we can set up a formula in terms of , where
represents the number of lines, and see where the formula is equal to
:
~anabel.disher