### Brain Teasers

# Heads or Tails

Logic
Logic puzzles require you to think. You will have to be logical in your reasoning.

You are blindfolded before a table. On the table are a very large number of pennies. You are told 128 of the pennies are heads up and the rest are tails up. How can you create two subgroups of pennies, each with the same number of heads facing up, while remaining blindfolded?

### Answer

Create a subgroup of any 128 pennies. Then flip over all 128. That group of 128 and the group of all the remaining pennies will have the same number of heads facing up.This works because the "tails" that you grab while making your subset of 128 will equal the "heads" that are left in the original pile. Once you flip your 128 coins over, these "tails" will turn into "heads" and the two groups will have a matching number of heads-up coins.

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## Comments

I DIDN'T GET IT A FIRST SO I TRYED IT

WITH RANDOM #'S OF COINS .IT REALLY WORKS

COOL TRICK.

WITH RANDOM #'S OF COINS .IT REALLY WORKS

COOL TRICK.

Call me dumb, but I just can't get my head around this one. I used an example of a batch of 130 pennies; 128 heads and 2 tails.

If I am blind folded and created a subgroup of another 128 pennies..surely they would be randomly heads and tails. I can't see how turning them over helps them match with the first set.

If I am blind folded and created a subgroup of another 128 pennies..surely they would be randomly heads and tails. I can't see how turning them over helps them match with the first set.

You're drawing 128 coins from the set of 130 you already have, not from a new pile of coins. You already know that 2 out of the 130 are tails. And there's nothing special about 128 - try the problem using 1 coin. Same logic.

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