A 0.20-km wide river has a uniform flow speed of 3.0 m/s toward the east. A boat with a speed of 8.0 m/s relative to the water leaves the south bank and heads in such a way that it crosses to a point directly north of its departure point. How long does it take the boat to cross the river

26.7 s

Explanation:

Given

Width of the river, = 0.2 km = 200 m

Speed of the rover, = 3 m/s

Speed of the boat, = 8 m/s

From the question, the boat would have to move westward. In moving westward, the angle will be

tan A = 3/8

tan A = 0.375

A = tan^-1(0.375)

A = 21°

Then, the velocity of the boat northward will be

v(north) = 8 cos 21

v(north) = 8 * 0.934

v(north) = 7.47 m/s

Therefore, the time taken would be

t = 200/7.47

t = 26.7 s

i think the answer is a, hope this is right, that would be my best guess.

uio

explanation: