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?
:
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
{{{x/6}}} + {{{y/4}}} + {{{y/12}}} + {{{x/6}}} = 2{{{1/3}}} 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