Archived Stumpers (with solutions)
STUMPER #1.14: SPIES!
(Did you solve something differently? There's almost always more than one way to solve
a math problem. Sometimes there's even more than one correct solution!)
Return to this week's stumpers View all archives Return to Math Gym home
1. Entry Code
___Congruent shapes are shapes that are exactly the same shape and size (though they can be rotated into different positions). On a spy mission, you find a secret door with six shapes on it. You need to press the two congruent ones to make the door open. If you choose the wrong pair you’ll set off an alarm and get caught. Which pair do you choose?
* Solution
The congruent shapes are A and D. 
2. Crack the Code
___Your spies have intercepted a secret message. They have learned that 1 means A, 2 means B, 4 means C, and 7 means D, and 11 means E. They also learned that other letters continue in the same pattern. Can you crack the code and read the message?
2211191 12541301 92106254 !
* Solution
“Get away now!” To solve the code, add 1 to A to get B, add 2 to B to get C, add 3 to C to get D, and so on.
