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anonymous

  • 4 years ago

Here's another math puzzle. ;D "Consider a string of n 7's, i.e., 7777...77, into which + signs are inserted to produce an arithmetic expression. For example, 7+77+777+7+7=875 could be obtained from eight 7's. For how many values of n could we insert + signs so that the resulting expression has a value of 7000?" From the 2004 AIME II.

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  1. anonymous
    • 4 years ago
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    well... 7*10=70 7*100=700 7*1000=7000 so 1000 7's? or n = 1000? unless there is something deeper to this problem...

  2. anonymous
    • 4 years ago
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    Not "what values of n" but "how many values of n".

  3. anonymous
    • 4 years ago
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    n = 28 i.e, 777 + 777 + 777 + .... 9 times + 7 = 7000

  4. anonymous
    • 4 years ago
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    Oh I am sorry there are two values of n 3 and 1

  5. anonymous
    • 4 years ago
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    False, that is not the answer.

  6. anonymous
    • 4 years ago
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    n = 1000, n = 100, n=28 hence 3 values

  7. anonymous
    • 4 years ago
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    sorry one value is 190 not 100

  8. anonymous
    • 4 years ago
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    Here's the solution for those who are interested. http://www.artofproblemsolving.com/Wiki/index.php/2004_AIME_II_Problems/Problem_14

  9. anonymous
    • 4 years ago
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    hey will take sometime I just found out there can be many such values

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