**Gotta stir up a little**

action around here. Who knows the answer to this?

Supply the missing number in this sequence of fractions:

2/5

7/3

5/10

15/9

17/?

Just give me the number. Save your explanation for later so as not to spoil it for all the whizzes amongst my readers.

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Weak guess: 14

Comment by son1http://ruberad.wordpress.com — March 22, 2006 @ 4:25 pm

Potentially 3 Phd readers and only one answer so far??

Comment by Bruce S — March 24, 2006 @ 4:13 pm

The difference between each pair increases by one each time. That leaves the missing number as either 10 or 24. But at least one number of each pair is the sum of the two preceding pair numbers. That leaves 24 as the only possible answer.

Comment by Bruce S — April 4, 2006 @ 4:14 pm

Aha. I caught the sum from the two preceding pairs, but missed the increasing absolute difference. I assume two more rules are the flip-flopping between < and > each time, and flip-flopping which of each pair is the sum (vs. which of each pair exists for the purpose of satisfying the increasing difference rule).

Without these extra two rules, the series does not continue indefinitely in a unique way, i.e. after the 17/24 pair, your two rules would be satisfied by 41/49, 41/33, 49/41, and 33/41.

There. Have I redeemed myself by my extra analysis?

Comment by son1http://ruberad.wordpress.com — April 5, 2006 @ 10:31 am

Is it possible to redeem myself?

Comment by son1http://ruberad.wordpress.com — April 5, 2006 @ 10:32 am