The upstream speed of a boat is 9 km/hr which is 300% more than the speed of stream . Find how much distance boat will cover in 5 hours while travelling in downstream .

Options

A. 66 km
B. 65.5 km
C. 67.5 km
D. 68 km

Answer

C

Explanation

Let the speed of stream be x km/hr
Then ,
Speed of boat in upstream = ` x xx (400)/(100) = 9`
`implies x = 2.25` km/hr
Speed of boat in still water = `9 + 2.25 = 11.25` km/hr
Distance covered in 3 hours in downstream
= `(11.25 + 2.25) xx 5 = 67.5` km