SOLUTION: Peter cycles to visit his grandmother and then returns home by the same route. He always cycles at 4 km/h when going uphill, 12 km/h when going down hill, and 6 km/h on level groun

Question 930977: Peter cycles to visit his grandmother and then returns home by the same route. He always cycles at 4 km/h when going uphill, 12 km/h when going down hill, and 6 km/h on level ground. If his total cycling time is 2 hours and 20 minutes, what is the total distance he cycles in km?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Peter cycles to visit his grandmother and then returns home by the same route.
He always cycles at 4 km/h when going uphill, 12 km/h when going down hill, and 6 km/h on level ground.
If his total cycling time is 2 hours and 20 minutes, what is the total distance he cycles in km?
:
let x = the level ground dist
let y = the hill distance
:
Assume grandma is at the top of the hill
Write a time equation; time = dist/speed
lev time + uphill time + downhill time + lev time = 2 hr 20 min
+ + + = 2 hrs
multiply by 12, cancel the denominators
2x + 3y + y + 2x = 28
combine like terms
4x + 4y = 28
simplify divide by 4
x + y = 7 km is the one way dist, 14 km is the total distance
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