Question

A large wooden raft is flowing with a river stream.
A man on the raft dives into river and swims down
the stream for 15 minutes and then he turns about
and comes back to the raft. The swimming speed
of man is 5 km/h in still water and the river is
flowing with speed 4 km/h. The distance moved by
the raft till the man comes back to raft is
(2) 2 km
(1) 1 km
(4) 4 km
(3) 3 km​

Answer 1

Answer:

1 km

Step-by-step explanation:

Given,

Speed of the stream/raft = 4 km/h

and speed of the man in still water = 5 km/h

Speed of the man downstream = 5 + 4 = 9 km/h

speed of the man upstream = 5 - 4 = 1 km/h

in 15 mins the raft moves = 1 km  

in 15 mins the man moves

5 km in 60 mins then 1.25 kms

upstream = 1km/hr

so 15 mins 0.25 kms

hence the distance moved by the raft till man comes back is 1 km  

Answer 2

Answer:

wrong explanation