Skip to main content

Heads or Tails



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.
Labels:

Comments

Post a Comment

Popular posts from this blog

Chris's Birthday

  If today is January 1st, and December 31st was Chris' birthday and she turned 8, and on December 30 Chris was 7, and this year Chris will turn 9, then next year Chris is turning 10.
Post a Comment
Read more

Suicidal Monks

  If there is only one monk with red eyes, then he sees all the others are brown-eyed, so he must be the red-eyed one. He kills himself the first night. If there are two monks with red eyes, then each sees one monk with red eyes and reasons that if this other monk is the only monk with red eyes, he will kill himself the first night. Neither monk kills himself the first night, so they each reason that they must have red eyes too. Both kill themselves the second night. If there are three, each expects the other two to commit suicide the second night. This doesn't happen, so each deducts that he must be a third, and the suicides happen the third night. Extends to four, five, etc. If the suicides happened n midnights after the tourist's remark, then there are n monks with red eyes.
Post a Comment
Read more

What is the 10 Digit Number?

  6210001000 There are 6 zeros, 2 ones, 1 two, 0 threes, 0 fours, 0 fives, 1 six, 0 sevens, 0 eights, and 0 nines.
Post a Comment
Read more