Quick calculations

This isn't really a way to do the calculation, but it is a way to answer the question easily...

Clearly, all the answers except the ones in the $3,000s are wrong, so let's ignore those.

On every compound interest question I've ever seen, the right answer is the one closest to, but above, the simple interest. $3,180 is simple interest ($3,000 x 1.06), and therefore $3,185 must be compound interest. So, that's what I would pick.

Knowing myself I would have calculated it, but that´s a better approach. Choices under 3.000 are ridiculous. Chocies much over 10% of 3.000 can be supposed to be too high. Of the remaining two, one is exactly the simple interest, so must be the remaining one. Most blibliography says that, when facing compound interest problems, go with simple interest "plus a few bucks".