A boatman row 1 km in 5 min along the steam and 6 km in 1 h against the stream. The speed of the steam is?

Let the speed of boat and steam be x and y km/h.
∴ Speed of boat along steam = (x + y) km/h
and speed of boat against stream = (x - y) km/h
According to the question,
x + y = 1 / (5/60) = 60/5
⇒ x + y = 12 ...(i)
and y - x = 6 ...(ii)
On adding Eqs. (i) and (ii), we get
2x = 18
x = 18/2 = 9
On putting the value of x in Eq. (i), We get
9 + y = 12
y = 12 - 9 = 3
Hence, speed of boat = 9 km/h
and speed of steam = 3 km/h