Question 932995
The road from village A to village B first goes uphill and then downhill.
 A bus moves uphill always at a speed of 30km/h and downhill always at a speed of 60km/h.
 Find the distance between A and B if a round trip from A to B and back without intermediate stops takes 4 hours.
:
Let d = distance traveled at 30 there and back
also
Let d = distance traveled at 60 there and back

:
Write time equation, time = dist/speed
time uphill + time down hill = 4
{{{d/30}}} + {{{d/60}}} = 4
multiply by 60, cancel the denominators and you have
2d + d = 60(4)
3d = 240
d = 240/3
d = 80 km from A to B