a man swims downstream distance at 45 km in 2 hr if the speed of the current is 4.5 km/h then the time taken by the man to swim the 50% more distance in upstream is

Hi Let speed of man be v Now in downstream effective speed = v+4.5 Now as per given condition : (45/v+4.5) =2 so v+4.5=22.5 so we get v=18 Now distance required to cover in upstream = 45 (1.5)=67.5 Now therefore time = (67.5/v-4.5) (In upstream effective speed is speed of man - speed of current ) solving we get 67/13.5 so time = 5 hours.