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Nicole Fornabaio / rd.com

## Little question n ° 5:

Two people stand back to back. They each move away from each other on three feet. Then they both turn left and walk another four feet, then stop. Now how many feet apart are they standing?

A. 10

B. 7

C. 25

D. 5

ten / 100 daguimaging / Shutterstock

If you remember a2 + b2 = c2 math class rule, this is what will help you to solve this problem. This rule states that if you have a triangle, the sum of the squares of the two shorter sides is equal to the square of the longer side. And in this problem, the paths of the walkers form parts of triangles. You may want a pencil and paper to “draw” this problem and visualize the triangles.

Draw two lines labeled “three feet” for the distance they go away from each other. Next, draw two lines labeled “four feet,” going in opposite directions, for the distance traveled after their left turn. Now draw a line connecting the dots at the ends of these lines (representing where the people are now). This line represents the distance you are trying to calculate.

Now you have two triangles touching at the corners. Two sides of each are 3 feet and 4 feet (the distances traveled by each person). The unknown sides represent two halves of the distance you are trying to find. So decompose this Pythagorean theorem: Three is a, 4 is b. 32 + 42 = 9 + 16 = 25 = c2. Take the square root of 25 and you get 5, which is the longest side of these mini triangles. Five feet is half the distance between people. Five times two is ten! Here’s another three-sided puzzle: Try to figure out how many triangles are in this picture.

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## Trivia question # 6:

You are trapped in a room with two doors. Only one door will lead you out of the room safely, but you don’t know which one. A guard stands in front of each door. One keeper is always lying, the other is always telling the truth, but you don’t know which one is which. You can only ask a guard one question. What question do you ask, and what do you do after the keeper answers?

A. “What is the door to the safe?” Go through the door the guard tells you to.

B. “What is the door to the safe?” »Go through the other door.

C. “If I had to ask the other guard which door to the safe was, which door would he say? Go through this door.

D. “If I had to ask the other guard which door to the safe, which door would he say? »Go through the other door.

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