Question 20
Noppon travels from $A$ to $B$ and back along the same route. His speed is 12 km/h downhill and 4 km/h uphill. The outward trip takes 50 minutes and the return trip takes $1\tfrac12$ hours. Find the distance from $A$ to $B$ in km.
The route consists of uphill and downhill portions only, with the stated speeds throughout each portion.
The route consists of uphill and downhill portions only, with the stated speeds throughout each portion.