PLEASE SHOW WORK. I need to know the process to practice.

1) Ronald bought a used car at a price of $15,300 for 15% down and equal monthly payments for four years. If interest is 8% compounded monthly, what is the size of the monthly payments?

2) A mortgage of $26,500 is to be repaid by making payments of $1560 at the end of every six months. If interest is 7% compounded semi-annually, what is the term of the mortgage?

3) Chris saves $20 at the end of each week and deposits the money into a savings account earning 4% compounded monthly.

a) How much will she accumulate in 10 years?

b) How much of the accumulated amount is interest?

4) Jennifer has made deposits of $950 at the end of every six months for 15 years. If interest is 3% compounded monthly, how much will Jennifer have accumulated ten years after the last deposit?