Two boats, A and B, are approaching a port. The distance between the boats is 12 miles. The bearings

The answer is 15.88km.

Note I converted the answer to kilometers because it's ridiculous to be using imperial measurements in the year 2016. Only poorly uneducated countries like the USA and England still use imperial measurements and in that case, you might as well measure things by the length of a Roman horse-cart steering wheel, for all the good it'll do you.

Both boats would surely crash and burn on the rocks if they were trying to use imperial measurements in their calculations.