You wish to borrow $$600,000$ from Macquarie Bank to finance a property to live in$.$ You have a deposit of $$100,000$ and the property has a value of $$1,000,000.$ Just need help with part b please.

a$.$ What is the dollar amount of your monthly repayment $($including cents$)?$

R $=600,000/[1-(1+0\mathrm{.}0614/12)^-12$ x $30/0\mathrm{.}0614/12]=$ $$3651\mathrm{.}49$

b$.$ Reducing your discretionary expenses allows you to contribute an extra $$50$ every month on top of your monthly repayments in a$).$ By how many months do you reduce the term of your loan $($expressed to two decimal places$)?$