Fundamentals of Computer Programming - Old Questions

3. A machine is purchased which will produce earning of Rs. 20000 per year while it lasts. The machine costs Rs. 120000 and will have a salvage value of Rs. 20000 when it is condemned. If the 12 percent per annum can be earned on alternative investments, what should be the minimum life of the machine to make it a more attractive investment compared to alternative investments?