4. Shereen has a loan for $50,000 which will be repaid with 4 non-level annual (end-of-year) (10) payments. The interest rate on the loan is an annual effective interest rate of 10%. The first loan repayment is $30,000. The second loan repayment $20,000. The third and the fourth loan repayments are $Q. The loan is repaid after the fourth payment. (a) Calculate the principal in the second payment. (b) Find the value of Q.