please show manual calculations & formulas to get to answers not just an excel sheet or just the answers! much appreciated

3. A loan of $5000 is to be paid off with level payments at the end of each month at 3% compounded monthly. The amount of interest paid in the 61" payment is $2.24 and the amount of principal repaid in the 42nd payment is $70.31. Find: a) The amount of principal repaid in the 61" payment. b) The size of the level monthly payment. c) The number of months necessary to pay off the loan. d) The amount of interest paid in the 10 payment