11. While riding a horse, a competitor shoots an arrow toward a target. The speed of the arrow as it reaches the target is \( 85 \mathrm{~m} / \mathrm{s} \). If the horse was traveling at \( 18 \mathrm{~m} / \mathrm{s} \), at what speed did the arrow leave the bow? (Assume the horse and arrow are traveling in the same direction.)