Word Problem

Question

Ted walked for 30 minutes and biked for 60 minutes. He bikes four times faster than he walks. If the total distance traveled is 9 miles, then what was his walking speed in miles per hour?

Answer 1

Distance = rate x time

 

 D = R*T = RT  

 

 Total distance = distance walking + distance biking

 

               9    =     r(1/2)   +   (4r)(1)   <---- 30 minutes = 1/2 hour; he bikes 4 times as fast as he walks

 

              9    =   1/2 r   +  4r

 

             9    = 1/2r  +  8/2 r <---- common denominator

 

           9   = 9/2 r 

 

         (2/9)*9 = (2/9)(9/2) r

 

          r = 2

 

  He walks 2 mph and bikes 8 mph

 

  He walks 2 mph * 1/2 hr = 1 mile

  He bikes 8 mph * 1 hour = 8 miles

                  Total is 9 miles

 

The answer is in bold above and is PROVEN to be correct.