Question

On a glass entrance door, an arrow is pasted on the outside pointing to the new office. The top tape peels off, causing the paper to hang and flip downward. From inside the building, the arrow is now seen pointing Southwest. What was its original direction (as seen from outside)?

• A. Southeast
• B. Northeast
• C. Northwest
• D. North

Hint:

For mirror and flip problems, apply transformations step by step: flip by hinge axis, then account for mirror (glass) reversal.

Answer 1

The Correct Option is B

Step 1: Paper flipping effect.
When the top tape loosens, the paper flips downward 180° around the bottom tape axis. This reverses the arrow’s vertical orientation.
Step 2: Glass reversal effect.
Looking from inside through glass, left–right also appears reversed.
Step 3: Combine flips.
- If outside arrow was pointing Northeast, after flipping it points Southwest (since up ↔ down).
- Viewed from inside glass, Southwest is exactly what is seen.
Step 4: Conclude.
The original arrow direction (outside view) was Northeast. Final Answer: \[ \boxed{\text{B – Northeast}} \]