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Bunuel
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CAT Question :lol:

\(\sqrt{x+{\sqrt{x+\sqrt{x+\sqrt{x+...}}}}}=10\)

squaring both sides...
x + \(\sqrt{x+{\sqrt{x+\sqrt{x+\sqrt{x+...}}}}}=100\)
Which is basically-
x + 10 = 100
x=90




Bunuel
If \(x\) is a positive number and \(\sqrt{x+{\sqrt{x+\sqrt{x+\sqrt{x+...}}}}}=10\), where the given expression extends to an infinite number of roots, then what is the value of \(x\)?

A. 80
B. 90
C. 100
D. 110
E. 120


Are You Up For the Challenge: 700 Level Questions
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I've mentioned this in other threads with similar types of questions -- there are no official GMAT questions like this. These are all prep company questions. The GMAT cannot test infinite sums (of fractions or of roots) because the first thing you need to do to answer these types of questions is prove the sum "converges" (it doesn't grow to infinity, and it gets closer and closer to a single value), and that requires calculus, which isn't tested on the GMAT.

So while the 'trick' that can be used to solve these questions is interesting, it's not something anyone will need on the test.
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Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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