Please explain how you reached the answer and show your work and mathematical calculations:
John currently has $20,000 in his savings account. He plans to put an additional $1500 into the savings account at the end of each quarter for 3 years and $2000 into the savings account at the end of each quarter for the following 2 years. How much will he have in 5 years if the interest rate is 7% APR with quarterly compounding?