can someone answer all parts please

Konstantin buys a house by making a down payment of $125,000.00 and taking out a mortgage for $375,000.00. The term of the mortgage is 4 years, and the amortization period is 15 years. Konstantin will make weekly payments and the mortgage rate is rll) = 3.250%. a) How much are the weekly payments? b) If Konstantin wants to reduce the weekly payments to $400.00, how much would the down payment have to be? $ c) If another bank offers Konstantin an equivalent mortgage (original down payment, same term, amortization period, payment periods) but with $625.89 weekly payments, what nominal interest rate (1) are they charging? (Remember, write 3.456 not 0.03456!)