Amber made regular equal deposits into a savings account at the end of every month for 2 years. The investments were earning 6.90% compounded quarterly and grew to $13,375 at the end of 2 years.

a) Calculate the size of the month end deposits. Round to the nearest cent

b) How long will it take for the $13,375 to accumulate to $43,780 if the interest rate remained the same and he continued making the same month-end deposits throughout the term? Express the answer in years and months, rounded to the next payment period