Home » Aptitude » Boats and Streams » Question
  1. A man rows down a river 15 km in 3 hrs. with the stream and returns in 7
    1
    hrs,
    2
    The rate at which he rows in still water is
    1. 2.5 km/hr
    2. 1.5 km/hr
    3. 3.5 km/hr
    4. 4.5 km/hr
Correct Option: C

Let speed of person in still water = p kmph and speed of current = q kmph

∴ p + q =
15
= 5 kmph ........( 1 )
3

& p – q =
15
15
2

p - q = 2 kmph ......( 2 )
On adding equations ( 1 ) and ( 2 ) ,
2p = 7 ⇒ p =
7
= 3.5 kmph
2

We can find the required answer with the help of given formula : :
Here, p =
15
= 5 kmph
3

q =
15
15
2

q = 2 km/hr
Speed of Boat =
1
(p + q)
2

Speed of Boat =
1
(5 + 2) = 3.5 kmph
2



Your comments will be displayed only after manual approval.