Boats and Streams Model 4: The Round Trip

04 Try it yourself Interactive

The round trip, one step at a time

Set the rower, the current and the total time for the whole journey. The solver builds both travelling speeds, computes the honest average twice over — once from the speeds and once from b and s — then turns the total time into a distance and checks the two legs add back up.

b 10, s 2, 5 hours in all

avg 9.6 not 10 · 24 km each way

Try a 9 km/h boat on a 12 km/h river. There is no return journey at all, so the solver refuses rather than printing the number the formula would still happily produce.

Press Next to work through it one step at a time.

Downstream–

Upstream–

True average–

One way–

step 0 / 0