Interesting problem... even more interesting solution

[440bx]

Hello,

What follows is, at best, only indirectly related to Pascal or programming in that it tests one's abilities to visualize solutions to a problem.

The problem is one given to elementary school children in China.  It is presented in youtube. Link: https://www.youtube.com/watch?v=3g8voItQD0c

I invite those interested in problem solving to take a crack at it.

For the record, I did solve the problem but not the way I would have liked to have solved it.

Have fun!

[MathMan]

Being the show-off that I am I posted my solution here initially, sorry 

Just for the record - I solved it too, mathematically, as I usually do.

[Thaddy]

This is an elementary school problem. What's the fuzz?

[440bx]

Just for the record - I solved it too, mathematically, as I usually do.

That's how I solved it too but the really beautiful solution, which he gives at the end, I missed.

[Thaddy]

Did I miss something in removing the noise? Took less than two seconds to solve it when I knew the constants and the length of the video.
The Chinese are right.