Shiny Side of the KnifeAlgebra Level 4
Two brothers had a flock of sheep. They sold the flock and got as many rupees for every sheep as the number of sheep in the flock. The money was shared in the following way:
First, the elder brother took ten rupees from the cash, then the younger brother took ten rupees, after which the elder brother took ten rupees again and so on.
Finally, it turned out that at the last stage when it was the younger brother's turn to take money, there remained less than ten rupees. Therefore the younger brother took the rest of the money and the elder brother gave him his knife (belonging to the older brother) for the sharing to be fair.
What was the cost of the knife in rupees??