Multiple choice

A boat covers a distance of $14$ km in $4$ hours along the flow. What is the speed of the boat in still water if the speed of the flow of water is $2$ km/hr ?

  1. $2$ km/hr
  2. $3$ km/hr
  3. $2.5$ km/hr
  4. $1.5$ km/hr
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Speed along flow (downstream) = 14 km / 4 hr = 3.5 km/hr. Downstream speed = boat speed + flow speed. 3.5 = boat speed + 2, so boat speed = 1.5 km/hr.

AI explanation

The downstream speed is the distance of 14 km divided by the time of 4 hours, giving a speed of 3.5 km/hr. Using the downstream speed formula (boat speed + stream speed = downstream speed), we set up the equation x + 2 = 3.5. Solving for x gives 1.5 km/hr. The result is 1.5 km/hr.