Answer
It is necessary to deposit $177.58$ monthly in that account to accumulate $12,000 after 5 year.
Work Step by Step
1. The payment formula for a sinking fund is:
$PMT = FV\frac{i}{(1+i)^n-1}$
Where:
$FV = 12,000$
$i = \frac{r}{m}= \frac{0.0475}{12}$
$n = mt = 12 * 5 = 60$
So: $PMT = (12,000)\frac{\frac{0.0475}{12}}{(1 + \frac{0.0475}{12})^{60} - 1} = 177.58$
