What is the next number? question

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Discussion Overview

The discussion revolves around identifying the next number in a given sequence: 10, 13.33, 20, 26.66, 40, 46.66, 60, 66.66, 80, 100. Participants explore various methods and patterns to derive a potential answer, engaging in reasoning and speculation.

Discussion Character

  • Exploratory
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant suggests a method involving multiplying by 3, rounding off, dividing by 10, and subtracting 1, indicating a possible pattern.
  • Another participant proposes that any chosen number could lead to a formula that fits the sequence, implying flexibility in interpretation.
  • A different participant notes a realization of a pattern related to prime numbers after manipulating the sequence, although they express skepticism about the mathematical nature of such sequences.
  • Two participants propose that the next number in the sequence could be 106.66, indicating they arrived at the same conclusion independently.

Areas of Agreement / Disagreement

Participants express differing views on the methods to derive the next number, with some proposing specific calculations while others suggest broader interpretations. The suggestion of 106.66 as the next number is mentioned by multiple participants, but no consensus on the method to arrive at it is established.

Contextual Notes

Participants' approaches vary significantly, with some relying on mathematical manipulations while others question the validity of the sequence as a mathematical problem. The discussion includes assumptions about the nature of the sequence and the methods used to analyze it.

gsingh2011
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"What is the next number?" question

I saw this question online but an answer wasn't provided. I've thought about it for a long time but I can't find an answer. Can anyone solve it?

What is the next number?
10, 13.33, 20, 26.66, 40, 46.66, 60, 66.66, 80, 100
 
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Multiply by 3, Round off, Divide by 10, Subtract 1... and look carefully.

OR pick absolutely number you like and it is easy to come up with a formula that will have the ones given in order followed by the number you picked.
 


Bill Simpson said:
Multiply by 3, Round off, Divide by 10, Subtract 1... and look carefully.

OR pick absolutely number you like and it is easy to come up with a formula that will have the ones given in order followed by the number you picked.

Wow, did you figure that out right now or have you seen it before?

I did the multiplying three thing myself, and I kind of found a pattern, but dividing by ten and subtracting one was genius.
 


I had never seen this before.

I stared at it for a couple of seconds, multiplied to get rid of the fractions, saw there was a trailing zero on every number, dropped those, stared at it for a couple of seconds and realized PRIMES!

But, as I said in my first reply, these "what is the next number" often aren't really "math."
 


So the next answer is 106.66?
 


QuantumJG said:
So the next answer is 106.66?

That's what I got.
 

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