Question

A boat takes 2 hours more to travel 45 km upstream than to travel the same distance downstream. If the ratio of the speed of current to the speed of boat is 1 ∶ 4, then find the speed of the current.

• A. 5 km/hr
• B. 9 km/hr
• C. 3 km/hr
• D. 6 km/hr

Answer 1

Answer:

C. 3 km/hr

Let the speed of current and speed of boat be 'x' km/hr and '4x' km/hr respectively. ⇒ 45/(4x - x) = 45/(4x + x) + 2 ⇒ 45{(1/3x) - (1/5x)} = 2 ⇒ 45(2/15x) = 2 ⇒ x = 3 km/hr