The Winning Combination
Logic puzzles require you to think. You will have to be logical in your reasoning.
You are in a game show with four other contestants. The objective is to crack the combination of the safe using the clues, and the first person to do so will win $500,000.
The safe combination looks like this:
????????
A digit can be used more than once in the code, and there are no leading zeroes.
Here are the clues:
1. The third set of two numbers is the same as the first set reversed.
2. There are no 2's, 3's, 4's or 5's in any of the combination.
3. If you multiply 4 by the third set of numbers, you will get the fourth set of numbers.
4. If you add the first number in the first set with the first number in the second set you will get 8.
5. The second set of numbers is not greater than 20.
6. The second number in the second set multiplied by the second number in the fourth set equals one higher than the numbers in the first set.
And get moving, I think another contestant has almost figured it out!
Answer
The combination is 71191768.
From the second clue, we know that there are no 2's, 3's, 4's or 5's in any of the sets. Therefore, only 1's, 6's, 7's, 8's and 9's could be in the remaining spots.
Clue 3 says if you multiply 4 by the third set of numbers you will get the fourth set of numbers. From this, you can tell a 1 is the first number in the third set  any other number would be too high.
11 * 4 = 44
16 * 4 = 64
17 * 4 = 68
18 * 4 = 72
19 * 4 = 76
Of these, 17 * 4 and 19 * 4 are the only ones that are possible; as the answer of the other numbers contains a number which we know is not in the combination.
Now we skip all the way to clue 5, which tells us the second set of numbers is not greater than 20. This means that the first digit of that set is also a 1.
So far, we know this much:
??1?1???
Now, we can come to clue 4, which tells us if you add the first number in the first set with the first number in the second set you will get 8. The first number in the second set is 1, so the first number in the first set must be 7. Since the first clue tells us the first set is the third set reversed, and we know that a 1 is the first number in the third set, a 1 must be the second number in the first set and a 7 must be the second number in the third set.
So far, we know this much:
711?17??
Now, the third set (17) multiplied by 4 will get us 68. Now we know the fourth set is 68.
711?1768
Now we come to the final clue. This tells us the second number in the second set (unknown) multiplied by the second number in the fourth set (8) equals one higher than the numbers in the first set. We know that the first set is 71, so adding one to that (72) and then dividing it by 8 will get us 9. So, the finished combination is:
71191768
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Comments
cuteandditzy
Dec 01, 2006
 Wow! There was alot to that teaser but it was very fun working out, even if it did take a few minutes. Very creative. Great job! 
scallio
Dec 01, 2006
 Very challenging... well for me at least! Fun to solve.

blondebookworm
Dec 01, 2006
 Really fun teaser, but too long for me. 
avalonsdad
Dec 04, 2006
 clue #5 is not needed, good teaser though 
teddybair
Dec 04, 2006
 This was a fun one to solve. Keep up the good work! 
thompson1
Dec 18, 2006
 It was pretty fun, but clue #5 was definitely not needed 
(user deleted)
Dec 29, 2006
 The answer above doesn't account for zero's. The definition states "no leading zero's". Here's an alternate abridged answer:
1. Possible digits for any set are 016789 (2). The first number in the first set and the first number in the second set adds to 8 (4). They are neither 0,8 nor 8,0 (definition of no leading zeros). Nor are they 1,7 (as the second set of numbers would be 70+ which is greater than 20 (5). Therefore they are 7,1  yielding: 7?1?????.
2. The second number of the third set is a 7 (1), yielding: 7?1??7??.
3. The first set is a number between 7079. The second number of the second set and second number of the fourth set are 8,9 in some order as multiplied together are the only digit combinations that satisfy clue 6. That order cannot be 8,9 as no number ending in 9 is divisible by 4 (3), therefore it is 9,8 which makes the second set of numbers 19.
4. The first set is 71 as it is one less than 9x8=72 (6), the third set of numbers is 17 (1), the forth set of numbers is 17x4=68 (3).
Answer: 7119176 
Jon0513
Jan 05, 2007
 That was really good, you should make more like these. 
cecepeach83
Jan 18, 2007
 I agree! quite entertaining. I have no idea how I got to the answer but it wasn't either of the ways offered thus far and it only took me 4 minutes. (mental note: I should figure that out) Clue 5 was definitely not necessary. Please make more of these! This was great. 
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