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On an uphill hike, Ted climbs at a rate of 3 miles an hour. Going down, he runs at a rate of 5 miles an hour. If it takes him 40 minutes longer to climb up than run down, what is the total length of Ted's hike?

 Nov 4, 2017

Best Answer 

 #2
avatar+129899 
+4

Let D be 1/2 of the  Diistance

 

And 40 min  2/3 hr

 

So   using Distance / Rate  = Time in Hours .......we have that

 

D/3  =  D/5   + 2/3    simplify

 

D/3  +  [3D + 10] / 15     cross-multiply

 

15D  = 3[ 3D + 10]

 

15D  =  9D + 30     subtract 9D from both sides

 

6D  = 30   divide both sides by 6

 

D  = 5 miles

 

So...the total distance is twice this  =  10 miles

 

 

cool cool cool

 Nov 4, 2017
 #1
avatar
+1

Let the time it takes to hike downhill =T

Distance = Speed x Time

5T =3(T+40), solve for T

5T = 3T + 120

5T - 3T = 120

2T = 120

T =120 / 2

T =60 - minutes, or 1 hour, to hike downhill.

Distance =1 x 5 mph=5 miles.

 Nov 4, 2017
 #2
avatar+129899 
+4
Best Answer

Let D be 1/2 of the  Diistance

 

And 40 min  2/3 hr

 

So   using Distance / Rate  = Time in Hours .......we have that

 

D/3  =  D/5   + 2/3    simplify

 

D/3  +  [3D + 10] / 15     cross-multiply

 

15D  = 3[ 3D + 10]

 

15D  =  9D + 30     subtract 9D from both sides

 

6D  = 30   divide both sides by 6

 

D  = 5 miles

 

So...the total distance is twice this  =  10 miles

 

 

cool cool cool

CPhill Nov 4, 2017
 #3
avatar+205 
+1

Thank you so much!

joebob  Nov 4, 2017

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