Question 1028108: Fred rode his bike up a mountain at 12 km/h and then back down at 48km/h. If he made the round trip in 1hr 20mins how far is it up the hill? Found 2 solutions by josmiceli, MathTherapy:Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website! Let = the distance in km from bottom to top of hill
Let = time in hours to go up the hill
----------------------
Convert 1 hr 20 min to hrs: hrs
---------------------- = time in hrs to go down the hill
----------------------
Equation for going up the hill:
(1)
Equation for going down the hill:
(2)
---------------------------
By substitution:
(2)
(2)
(2)
(2)
(2)
and
(1)
(1)
(1)
The distance in km from bottom to top of hill
is 12.8 km
--------------
check:
(2)
(2)
(2)
(2)
(2) km
OK
You can put this solution on YOUR website!
Fred rode his bike up a mountain at 12 km/h and then back down at 48km/h. If he made the round trip in 1hr 20mins how far is it up the hill?
Let distance, one-way be D
Then time up-hill = , and time downhill =
We then get the following TIME equation: ____
4D + D = 64 ------ Multiplying by LCD, 48
5D = 64
D, or distance = , or
