Michael is 53 and earns gross $125,000 a year. His partner Leslie is 51 and earns $112,000 a year. They save 10% of their joint income most years, but are prepared to live more frugally when they both retire in 12 years time. Assuming inflation averages 4% a year and that the real time value of money is 2% a year, calculate the average extra monthly saving required from the couple in order to accumulate enough to fund their retirement at 75% of their current net income. Their average tax rate can be assumed to be 25% over the next 12 years. Assume the pair will both die on Michaels 82nd birthday.