21) (20 pts) Rob and Laura wish to retire in 25 years. They want to be able to withdraw $40,000 per year in today's dollars during retirement. They expect to earn 8% during their saving years and a 2% real return during their retirement. They expect to live 30 years after retirement, hence making 30 annual withdrawals. Inflation will average 3% per year. a) What is the value of their first withdrawal in 26 years? b) How much do they have to have saved in 25 years to fund their retirement? c) What equal annual payment must they make during their saving years (25) to meet this goal? d) If they could put away one lump sum today to fund the retirement, how much would it be