Question

A boat covers 24 km upstream
and 36 km downstream in 6
hours, while it covers 36 km
upstream and 24 km down-
stream in 6 hours. The
speed of the current is:
​

Answer 1

Answer:

Speed = distance/time

Let the speed of boat be ‘a’ and speed of stream be ‘b’

Relative speed of boat going upstream = a – b

Relative speed of boat going downstream = a + b

Given, boat goes 24 km upstream and 28 km downstream in 6 hrs. It goes 30 km upstream and 21 km downstream in hrs

------- (1)

Also, ------ (2)

Multiplying eq1 by 3 and eq2 by 4 and (1) – (2)

⇒ a - b = 6 ------- (3)

Substituting value of (a - b) into eq1

⇒ a + b = 14 ------ (4)

From (1) and (2), we get

a = 10 km/hr and b = 4 km/hr