Answer
It is better to receive 3 percent interest every 6 months.
Work Step by Step
If you receive 3 percent interest every 6 months, the actual amount of interest received in a year will be:
$$(1+.03)^2 -1\\ 1.03^2-1\\ 1.0609-1 \\ .0609$$
Thus, we see that receiving 3 percent every 6 months will result in a higher annual rate than 6 percent interest.