The question:

Answer at the back of the book: sqr(5000+2500sqr3) kmA cruise ship sailed north for 50km. Than the captain turned the ship eastward through an angle of pi/6 and sailed an additional 50km. Without using a calculator, determine an exact expression for the direct distance from the start to the finish of the cruise.

Seems pretty simple and maybe I'm thinking of this question the wrong way, but I can't seem to figure out where they got that answer.

All helpgreatlyappreciated!