The speed of a boat in still water is 24 km/hr and the speed of the stream is 8 km/hr. It takes a total 20 hours to row upstream from point X to Point Y and downstream from Point Y to Point Z. If the distance between X to Y is one third of the distance between Y and Z. What is the total distance travelled by the boat (both upstream and downstream)?

Boat speed in still water = 24 km/hr, stream speed = 8 km/hr. Upstream speed = 24 - 8 = 16 km/hr. Downstream speed = 24 + 8 = 32 km/hr. Let XY = d, then YZ = 3d. Time upstream: d/16 hours. Time downstream: 3d/32 hours. Total time: d/16 + 3d/32 = 20 hours. Solving: 2d/32 + 3d/32 = 5d/32 = 20, so d = 128 km. Total distance = d + 3d = 4d = 512 km. Claimed answer correct.