Independent solution

How to solve this Savings and Withdrawal Equation question

Setup

Setup

Convert 8% annual effective to its equivalent monthly rate. Savings deposits are made at the beginning of each month, and retirement withdrawals are made at the beginning of each year.

j=(1.08)1/121=0.006434j=(1.08)^{1/12}-1=0.006434

Model

Model

Value both streams at the retirement date. The four withdrawals form an annuity-due, while the 216 monthly deposits form an accumulated-value annuity-due and are moved to the same date.

25000a¨40.08=Xs¨216j(1.08)1525000\ddot a_{\overline{4}|\,0.08}=X\ddot s_{\overline{216}|\,j}(1.08)^{-15}

Compute

Compute

Solving the equation gives a monthly deposit of 240.38, which rounds to 240.

X=240.38X=240.38

Answer

Answer

The calculation gives 240 for savings and withdrawal equation, matching published choice C.

X=240(C)\boxed{X=240\quad\text{(C)}}