Hello,Originally Posted byCelia

the direction perpendicular to the shore(s) has a bearing of 0°.

The way of the boat through the water, the current of the river and this perpendicular direction form a right triangle. (See attachment)

the way per second of the boatover groundis (use Pythagorian Theorem):

to a) You have to steer the boat against the current with an angle of:

on your way back you must steer: 180°-4.25°=175.75°

to b) The boat has to travel 2 * 150 m = 300 m over ground. The boat travel 6.73 m/s over ground. So it'll take

Greetings

EB