Advanced TVM $2$

Your sister will start college in five years. She just informed your parents that she wants to go to Georgia Southern University. It will cost $$20,000$ per

year for four years $($cost assumed to come at the beginning of each year$).$ Anticipating her ambitions, your parents have saved already $$15,000$ and

will continue to invest at the end of each month for the next five years.

How much more will your parents have to invest each month for the next $5$ years to have the necessary funds for your sister's college education?

Assume the interest rate is $10\%$ annual compounding.