# How long will it take Marie to saw another board into 3 pieces?

So this is supposed to be really simple, and it’s taken from the following picture:

Text-only:

It took Marie $10$ minutes to saw a board into $2$ pieces. If she works just as fast, how long will it take for her to saw another board into
$3$ pieces?

I don’t understand what’s wrong with this question. I think the student answered the question wrong, yet my friend insists the student got the question right.

I feel like I’m missing something critical here. What am I getting wrong here?

Haha! The student probably has a more reasonable interpretation of the question.

Of course, cutting one thing into two pieces requires only one cut! Cutting something into three pieces requires two cuts!

——————————- 0 cuts/1 piece/0 minutes

—————|————— 1 cut/2 pieces/10 minutes

———|———–|——— 2 cuts/3 pieces/20 minutes

This is a variation of the “fence post” problem: how many posts do you need to build a 100 foot long fence with 10 foot sections between the posts?

Answer: 11 You have to draw the problem to get it…See below, and count the posts!

|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|
0-----10----20----30----40----50----60----70----80----90---100