# Tag Info

Accepted

### How can 64 = 65?

This is a famous physical puzzle that can be tied to the fibonacci series. To answer the question as posed, the issue is that the two slopes are different ($\frac25$ vs $\frac38$). Note that all ...
• 22.4k

### How can 64 = 65?

The diagram is misleading, as it hides a gap in the middle of the second configuration. This is what we actually get if we rearrange the shapes in question. Notice that the diagonal “bows” slightly, ...
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### XOR - Is it possible to get a, b, c from a⊕b, b⊕c, a⊕c?

If you're given just a⊕b and b⊕c, then you can calculate ...
• 1,448

Does this count?
• 759
Accepted

### 3:3! It's a football score!

If you are allowed to use decimals, then

### 1 2 3 4 5 6 7 8 9 = 100

Note: This answer only applies prior to the edit that clarifies that the expression on the left must evaluate to 100, rather than simply the equation being true. If you allow exponents, you can get ...
• 12.7k
Accepted

• 13.5k
Accepted

• 33.3k

• 7,883

### 4 Attempts to Guess a Number Between 1-15

Yes. Guess 1st set (1,3,5,7,9,11,13,15) -> If the number is in the set, write down 1 Guess 2nd set (2,3,6,7,10,11,14,15) -> If the number is in the set, write down 2 Guess 3rd set (4,5,6,7,12,13,14,15)...
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• 693

### 4 Attempts to Guess a Number Between 1-15

A simple way is to pick the number $X$ which is half-way through the range and ask Is it less than $X$? From the answer you can discard either the lower half or the upper half of the range. ...
• 11k

### 9-5=5? Matchstick problem

Another solution:
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### Number 88 from the digits 2, 0, 1 and 7?

No rules? Looks like 88 to me if I squint.
Accepted

### Doubling/tripling puzzle: make 1 from 1536 in as few steps as possible

As Jo has already shown, this can be accomplished in To help visualize this problem, we can imagine: Proving minimality:
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• 35.4k
Accepted

### 9-5=5? Matchstick problem

Here's one way: For the image-impaired:
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Accepted

### Why are all numbers from 1 to 2N covered by weights with powers of 3?

It helps to think about the scale not in terms of balancing two objects, but in terms of creating a weight difference between the two sides. (If you want to balance out an object, you simply put ...
• 140k
Accepted

### Five loaves and the extra traveller

Such an old chestnut! Each of them eats 5/3 loaves. The first traveler contributes 3 loaves, eats 5/3 himself, and gives 4/3 to the extra traveler. The second traveler contributes 2 loaves, eats 5/3 ...
• 44.8k

### Building a 2 mile runway on a 1x1 mile island

Build two straight runways side to side, 1 mile long each. Then, put a portal-conducting surface at the end of the first runway and another one at the beginning of the second one. Finally, use your ...
Accepted

### Can you explain these equations?

The equations are I don't really feel like calculating all of them, but for the first and second one: The edit history hint helped a lot with this one. Edit: For completeness here are all three:
• 496

Only top scored, non community-wiki answers of a minimum length are eligible