1.

A river flows at 4 km/hr. The speed of a boat in downstream is thrice the speed of that boat in upstream. Find out the speed of the boat in still water?1. 8 km/hr2. 4 km/hr3. 6 km/hr4. 12 km/hr

Answer» Correct Answer - Option 1 : 8 km/hr

Given:

Speed of river flow = 4 km/hr

Speed of boat in downstream = 3 × Speed of boat in upstream

Concept used:

Speed of boat in downstream = Speed of boat in still water + speed of river flow

Speed of boat in upstream = Speed of boat in still water - speed of river flow

Calculation:

Let the speed of boat in still water be 'x' km/hr

Let the speed of boat in downstream and upstream be 'd' km/hr and 'u' km/hr respectively

Then, as per question

d = 3 × u

⇒ x + 4 = 3×(x - 4)

⇒ x + 4 = 3x - 12

⇒ x = 8

∴ Speed of boat in still water is 8 km/hr.



Discussion

No Comment Found

Related InterviewSolutions