A mine is for sale for $240000 it is believed the mine will produce a profit of 65000 the first year but the profit will decrease $5000 each year after that, eventually reaching zero, whereupon the mine will be worthless. Determine the rate of return this $240,000 investment would produce for the purchaser of the mine? You may try 15% and 18% interest rates as your first estimates and find the rate of return through interpolation.