



 
A person who really understands what is going on would realize that 9 = 8.99999... and would be able to guess the final digit in the sum up to eight terms. If you are not such a person, then you have to work a bit. You are told that for some starting point x, the infinite sum
equals 9. So factor out the x to get
and set 10x/9 = 9. Now solve for x. Your task is to add the first eight terms, x + x/10 + ... + x/10000000. Chris  


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