How is the value of the increase in land area (200 square meters) – which became apparent to its owners after purchasing it in 1989 – to be paid? Is it at the purchase price at that time, or at the 2010 price, taking into account the percentage increase in the price of gold, wheat, or the dollar?

The inquirer only acquired ownership of the area equivalent to the money paid in 1989. Any excess remains the property of the seller and must be returned to him. If the inquirer wishes to purchase it, it must be at its current price (2010). If the inquirer has constructed a building on the excess area, he must be compensated for the value of what he built therein.