Brain Teasers
Seven Sportsmen
Seven sportsmen are standing in a row. Each sportsman has a different 1-digit number. The product of the first three, the product of the middle three, and the product of the last three are all equal.
What's the middle sportsman's number?
What's the middle sportsman's number?
Hint
Figure out what the numbers are, and then eliminate the impossibilities.Answer
Let their numbers be a through g, we have abc=cde=efg.5 or 7 cannot occur, because they are prime and no other 1-digit number contains them. Therefore, the numbers are 1, 2, 3, 4, 6, 8, 9.
Since abc=efg, abcdefg/d is a perfect square. 1*2*3*4*6*8*9=2^7*3^4, and d can be only 2 or 8.
If d=2, the numbers 1, 3, 4, 6, 8, 9 can be made into 1*8*9=3*4*6=72, and we can have c=9, e=4: 9*2*4=72.
If d=8, the numbers 1, 2, 3, 4, 6, 9 can be made into 1*4*9=2*3*6=36, but 36 is not divisible by 8.
Therefore, the middle sportsman's number is 2.
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Comments
Silly me !!! I messed up the one-digit clue and used 1 thru 7 and tried to solve but couldn't !!!
Good one !!
Good one !!
You lost me with your answer, but I got the correct answer writing it out and had fun doing it!
4 - 3 - 8 - 2 - 5 - 1 - 9
4 - 3 - 8 - 2 - 5 - 1 - 9
Scallio, you're wrong. I said the PRODUCT, not the SUM.
confusing but fun!!!
Good teaser! It was extremely fun
hmmmm...i'm lost. i guess it's just not my thing. interesting, though.
Pretty nice solution. I actually solved it pretty quick just by guessing.
You need to satisfy ab = de and cd = fg. I tried d = 0 and 1 and quickly saw those don't work. When I got to d = 2, I saw 3 * 6 = 2 * 9 and 2 * 4 = 1 * 8.
You need to satisfy ab = de and cd = fg. I tried d = 0 and 1 and quickly saw those don't work. When I got to d = 2, I saw 3 * 6 = 2 * 9 and 2 * 4 = 1 * 8.
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