Series & Sequences: Express 7.54545454545 as Rational Number

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Homework Statement




Express 7.54545454545 . . . as a rational number, in the form p/q
where p and q are positive integers with no common factors.
p = ? and q = ?


This problem is nothing like I've seen before, so I don't even have a clue on how to start it.
 
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There is a usual method of multiplying the number by 100 and subtracting and then dividing a few things to get a result (or tweaking it a little bit to fit your number). Have you seen this before? What methods have you used in the class or book you got this from? That is usually a good start.
 
Well I've seen the general theories ans tests but our teacher never gave us an example or a situation like this one, that is why I can't figure out how to even start the problem.
 
Try what VeeEight suggested. If s=7.54545454545 . . . what is 100*s-s?
 
Yeah I posted that,but they deleted it and I got in trouble for giving them full answers so try doing something with s and SOMETHINGs and SUBTRACT them to get something S=something here. Then divide.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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