Loan repayment questions last part

A man borrows $30 000 at 14% p.a. He pays off the loan in equal monthly instalments over 15 yrs. Interest is calculated on the amount outstanding at the start of each month and he pays his instalment at the end of each month. What will be his monthly payment? What will his monthly payment be, if after 2 years the interest rate changes from 14-15% p.a and at the end of the 3rd year it changed from 15-16% p.a?

A woman borrows $10 000 at an interest rate of 12% p.a on the outstanding balance. If the instalments are paid in equal annual instalments, how much are her instalments if the loan is to be paid off in 5 years? How much would she have saved by making monthly payments with the interest calculated monthly?

These are the last two questions, sorry for posting up so many ><"" I'm just having a lot of trouble with them, thank you so much for any help given.