## anonymous 5 years ago If Bill rides his bike 3 miles to Fred's house and then walks with Fred the remaining 1 mile to school, it will take him 30 min. But if he rides the entire distance, it will take him only 20 minutes. Find his biking speed and walking distance?

r * t = d, therefore t = d/r Let x and y equal Bill's riding speed and walking speed in miles per hour respectively. Then from the problem narrative,$\left\{\frac{30}{60}\text{=}\frac{3}{x}+\frac{1}{y},\frac{20}{60}=\frac{4}{x} \right\}$Solve the simultaneous equations for x and y.$\{x=12,y=4\}$Bill's riding speed is 12 mph and walking speed is 4 mph. The only "walking distance" in the problem was the one mile from Fred's house to school.