Question

A swimmer reaches the other bank of a flow
river exactly opposite to the starting point the
swimming at 2 km/hr while maintaining 150
the flow, then time taken by him to cross the
1 km wide is
(1) 30 min
(2) 1 hr
(3) 2 hrs
(4) 20 min​

Answer 1

Answer:

1 Hr

Explanation:

A swimmer reaches the other bank of a flow

river exactly opposite to the starting point the

swimming at 2 km/hr while maintaining 150

the flow, then time taken by him to cross the

1 km wide is

(1) 30 min

(2) 1 hr

(3) 2 hrs

(4) 20 min​

swimming at 2 km/hr while maintaining 150 the flow

velocity in direction of Flow = 2Cos150  = -2Cos30  = -√3  km/hr

=> Velocity of Flow = √3 km/hr

Velocity in direction of Traget Point (width) = 2 Sin150 = 2Sin30 = 1 km/Hr

Width = 1 km

Time Taken = 1/1  = 1 Hr