(Solved): The speed of a boat in still water is v. The boat is o make a round trip in a river whose current tr ...

The speed of a boat in still water is \( v \). The boat is to make a round trip in a river whose current travels at speed \( u \). Deeive a formula for the time needed to make a found trip of total distance \( D \) it the boat makes the round trip by moving upstream and back downstream. Express your answer in terms of the variables \( D, \mathrm{H}_{\text {, }} \) and \( u \). Part \( \mathrm{B} \) Derive a formula for the time nooded to make a round trip of total distance \( D \) it the bouk makes the round trip by moving cirectly across the river and back. Express your answer in terms of the variables \( D, v \), and \( u \).