An investment of P 275000 in a new machine could reduce the annual cost of operations by P 80000. It would cost P 12000 per year to maintain the machine which would last for 10 years with neglible scrap value. A constant annual deposit in a fund is made at an interest of 8% per annum to accumulate and receive the first cost of the machine in 10 years. 

Find the rate of return on the investment in percent.