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Brady rose his bike 70 miles in 4 hours. He rode at an average speed of 17 mph for t hours and at an average rate of speed of 22 mph for the rest of the time. How long did Brady ride at the slower speed? Use the variable t to represent the time, in hours, Brady rode at 17 mph.

 Jan 14, 2020
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Rate * t  = Distance

t is the time @ 17 mph

4hrs-t  is the time at 22 mph

 

17*t  +  22(4-t)   = 70

17t + 88 - 22t = 70

-5t = -18

t = 3.6 hrs   @ 17 mph  .4 hr @ 22

 
 Jan 14, 2020

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