A river is 400 feet wide and flows at 1 ft/s. A swimmer swims at 2 ft/second, straight across the river and back to where he started on the original shore. Find the time required to complete his trip.
To clarify, the turn around point is straight across the river.
(I have already been given the answer: 461 seconds)
t=(2d/vs)*(1/sqrt (1-(vr/vs)^2)), where vs is the velocity of the swimmer (√3 from Pythagorean theorem) and vr is the velocity of the river (1), and d is distance (800ft). Sorry I couldn't figure out how to attach or embed an image (novice here).
The Attempt at a Solution
I used this equation and got 566 seconds, which is decidedly not 461 seconds. Where did I go wrong?
Thanks in advance guys!