Here is one more problem for those of you love to think combinatorially 🙂

Consider a finite sequence of real numbers for which the sum of any seven consecutive terms is negative and the sum of any 11 consecutive terms is positive. Find the greatest number of terms of such a sequence.

Hint: Construct some concrete example and play with it!

You are welcome to send your solutions, comments, etc.

More later,

Nalin Pithwa