Aswimmer is moving in a square course in a river. the flow velocity of the river is 3 metre per second and the

velocity of swimmer relative to water is 5 metre per second. the total distance travelled by the swimmer is a 80m. fin the time taken to complete thr course

Assuming that the swimmer is moving at an angle of 45degrees relative to the ground the the velocity vecot of the swimmer relative to the ground is equal to the sum of the velocity vector of the river with respect to the ground and the velocity of the swimmer with respect to the river.

Therefore his velocity would be 5+3=8.So to travel a distance of 80metres he will take 10 seconds.