A system which was established with a cost of $1000000 five years ago has a market value of $ 5000 with a salvage value of $30000 after 1 year and $25000 after 2 year and $ 15000 after 3 year the annual worth of the challenger will be $ 65000 perform the replacement analysis at an interest of 10%. Calculate the real interest rate per month if the inflated adjusted rate is 3% and the inflation rate is 0.5%