First, draw a compass with all directions labelled. Then, draw lines in the directions indicated by the problem, taking the angles of direction into account. Then draw a line connecting the endpoints of the two lines together to form a triangle. Finally, use the Law of Cosines to determine the length of the third line.

AB2 = AC2 + CB2 - 2*cosACB*AC*CB

AB2 = 100 + 225 - 2*cos110*10*15

AB2 = 624.706244

AB = 24.99412419 miles

Therefore, they are approximately 25 miles apart.