A swimmer heading directly across a river that is 200 m wide reaches the opposite bank in 6 min 40 s. During this swim, she is swept downstream 480 m. How fast can she swim in still water

The speed of the swimmer in stil water is 0.5 m/s

Explanation:

Given;

total time taken to swim across = 6 mins 40 s = (6 x 60s) + 40 s = 400 s

width of the river, = 200 m

Please find the image attached for explanation.

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west