A river is flowing with speed of 1km/hr.A swimmer wants to go to point C starting from point A. He swims with a speed of 5 km/hr at an angle $\theta$with respect to the river. If $AB=BC=400m$ Then

Question

a)time taken by the man in 6 mins

b) time taken by the man in 8 mins

c)the value of $\theta=45 ^{\circ}$

d)the value of $\theta=30 ^{\circ}$