A straight one-mile stretch of highway, 40 feet wide, is closed. Robert rides his bike on a path composed of semicircles as shown. If he rides at 5 miles per hour, how many hours will it take to cover the one-mile stretch? Note: 1 mile = 5280 feet
Answer Choices
A. \dfrac{\pi}{11}
B. \dfrac{\pi}{10}
C. \dfrac{\pi}{5}
D. \dfrac{2 \pi}{5}
E. \dfrac{2 \pi}{3}