# Brantley and Shawna walk to Grandma's house at a rate of mi/hr. They ride their bicycles back at 8 mi/hr over the same route that they walked. It takes 1 hr longer to walk than to ride. How long did it take them to walk to Grandma's?

Time taken for walking journey was $1 \frac{1}{7} h r$
Let time taken for walking and cycling journey be ${t}_{1} \mathmr{and} {t}_{2}$ respectively. Since the distance of both the journey be same, $1 \cdot {t}_{1} = 8 \cdot {t}_{2} \left(1\right)$ and by condition ${t}_{1} = {t}_{2} + 1 \left(2\right)$
Substituting ${t}_{1}$ in equation (1) we get , $\therefore {t}_{2} + 1 = 8 \cdot {t}_{2} \mathmr{and} 7 {t}_{2} = 1 \mathmr{and} {t}_{2} = \frac{1}{7} h r \therefore {t}_{1} = 8 \cdot {t}_{2} = 8 \cdot \frac{1}{7} = \frac{8}{7} = 1 \frac{1}{7} h r$
Time taken for walking journey was $1 \frac{1}{7} h r$ [Ans]