Question

A river 91.4 m wide flows toward the south at 33.6 m/min. A girl on the west bank wishes to reach the east bank in the least possible time. She can swim 91.4 m in still water in 2.00 min. (a) How long does it take her to cross the river

Answer 1

2.0 min

Step-by-step explanation:

We are given that

Width of river,d=91.4 m

Time,t=2 min

Rate of flowing water of river=33.6/min

We have to find the time taken by girl to cross the river.

Speed of girl=
`v=(distance)/(time)=(91.4)/(2)=45.7m/min`

Time taken by girl=
`(distance)/(speed)`

Using the formula

Time taken by girl=
`(91.4)/(45.7)`

Time taken by girl=2.0 min