please help me solve these two questions

Person A starts working at 33 with no deposits. He retires at 65. His annual income is $50.000. He has to save some money to supp ort his after-retirement life from 65 to 85. The constant interest rate is 4% per year. if(1) he chooses to maintain his after-retirement spending at the rate of 80% of his pre-retirement income, how much money should he deposit every year? if (2) he would like to maintain a constant spending before and after retirement how much does he save every year