Today Donald purchased a cottage and a boat worth a combined present

value of $$390000.$ To purchase the cottage$,$ Donald agreed to pay $$60000$

down payment and $$2100$ at the end of each month for $20$ years. To buy the

boat, Donald was required to pay $$6000$ down payment and R dollars at the

end of each month for $4$ years. Determine R if j$12=12\%$