40. A man can swim in still water at a speed of 4kmph. He desires to c

1.	40. A man can swim in still water at a speed of 4kmph. He desires to cross a river flowing at aspeed of 3 kmph in the shortest time intervalIf the width of the river is 3km time taken tocross the river (in hours) and the horizontaldistance travelled (in km) are respectively3391 151)2)3) 4)4 4دیا7
Answer» Answer: Since he makes his STROKES normal to the RIVER current, the movement of the river will have no effect on the time of crossing the bank. The time will be, T= Speed Distance = 4 1 hr=0.25hr=15min. In the same time, he will GO down by Distance=Speed X time=3km/hr x 0.25hr=0.75km=750m

40. A man can swim in still water at a speed of 4kmph. He desires to cross a river flowing at aspeed of 3 kmph in the shortest time intervalIf the width of the river is 3km time taken tocross the river (in hours) and the horizontaldistance travelled (in km) are respectively3391 151)2)3) 4)4 4دیا7

Answer»

Answer:

Since he makes his STROKES normal to the RIVER current, the movement of the river will have no effect on the time of crossing the bank.

The time will be, T=

Speed

Distance

hr=0.25hr=15min.

In the same time, he will GO down by

Distance=Speed X time=3km/hr x 0.25hr=0.75km=750m