Sam left at 3:05. He walked at speed of 3.2 mph. 15 min later, Al starts running after him, and he caught up with Sam 10 min later. What was Al’s speed?

Question

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Answer 1

 

  Sam walked 3.2 mph for 15 min = 3.2 mph x 1/4 hr = 0.8 miles

 

  Then Al runs for 10 min which is 1/6 hr.  IN the same 10 minutes, Sam walks 3.2 mph x 1/6 hr =0.53  miles.

 

So Al ran for 0.8 + 0.53  miles = 1.3 miles or 1 and 1/3 miles in 10 minutes = 1/6 hr.

 

Rate = distance/time = 1 and 1/3 miles divided by 1/6 hr = 4/3 divided by 1/6 = 4/3 x 6/1 = 24/3 = 8 mph