DAY 424

ODDLY ADDICTIVE
Credit: GAMES Magazine - March, 2008
Burt Hochberg

Assume that the two sets of figures below are correctly aligned. Which set would you think adds up to the higher total?

987654321     123456789
  87654321     12345678
    7654321     1234567
      654321     123456
        54321     12345
          4321     1234
            321     123
              21     12
________1     1___________

Answer:

Both columns of numbers add up to the same total: 1,083,676,269. The zeros omitted from the numbers on the right are implied by the alignment of the column.

Explanation (by Philip Sakievich):  Notice the 1's in the set to the right. There are nine of them, each in the hundred-millions column. They total to nine hundred million. This corresponds to to the 9 in the first number at the top of the set to the left, which is also in the hundred millions column. There are eight 2's in the set to the right, each in the ten millions column. Each 2 stands for twenty million. Together they total to 160 million. This corresponds to the two 8's in the set to the left, each also in the ten millions column. Each 8 stands for eighty million, for a total of 160 million. The seven 3's to to the right total 21 million, corresponding to the three 7's on the left which also total to 21 million. And so on until the 9 in the ones column at the end of the set to the right, corresponding with the nine 1's in the ones column of the set to the left.

     

DAY 423

I 'm a two-digit decimal number. Reverse my digits and I'm one-tenth of my former self. Who am I?

Answer:

1.0

DAY 422

What is the most recent year that contains all even digits, before the year 2000?

Answer:

Since all digits must be even, it cannot be in the previous millennium.  So it must be 888.

DAY 421

HEADS OR TAILS

You are in a dark room and have 100 coins spread out in front of you. Ninety are facing heads up and ten are facing tails up. The coins are mixed up, and you cannot see which way they are facing. How can you sort the coins into two piles, such that each pile has the same number of coins facing tails up?

Answer:

Since the piles don't need to be the same size, make one pile of ten coins and one pile of the other ninety. Flip all of the coins in the pile of ten, and now both piles will have the same number of coins facing tails up.

Example:
Suppose you have three coins facing tails up in the pile of ten. This means there are seven coins facing tails up in the pile of ninety. If you flip all ten coins in the ten pile, you now have seven coins facing tails up - just as in the pile of ninety.

DAY 420

TWO BLIND MEN

A blind man goes to the mall and buys three pairs of red socks and three pairs of white socks. Another blind man is also at the mall, returning the three pairs of red socks and three pairs of white socks that he bought the day before. The two men bump into each other and all the socks are scattered on the floor, but each pair remains held together by a rubber band. The two blind men are able to gather the six pairs of socks together. Without any help, they are quickly able to sort the socks so that each man ends up with the same number and color of socks he started with - six red and six white. There is no indication on the socks as to their color. How do these two blind men do it?

Answer:

One of the men takes the rubber band off each pair. He keeps one sock for himself and gives the other to the other man.