Janelle has 5 hours to spend training for an upcoming race. She completes her training by running full speed the distance of the race and walking back the same distance to cool down. If she runs at a speed of 9 mph and walks back at a speed of 3 mph how long should she plan to spend walking back?

Answer:The distance cover by him walking back is 11.25 miles Step-by-step explanation:Given as :Time for Janelle to spend on training = 5 hoursThe  running speed of Janelle = 9 mphThe walking back with 3 mphLet The distance for running and walking is same i.e  D milesSO, Time = [tex]\frac{Distance}{Speed}[/tex]∴  5 =  [tex]\frac{D}{9}[/tex] +  [tex]\frac{D}{3}[/tex]Or, 5 × 9 = D + 3 DOr, 45 = 4 D∴   D = [tex]\frac{45}{4}[/tex] = 11.25 milesHence The distance cover by him walking back is 11.25 miles   Answer