A sailor can row a boat 8 km downstream and return back to the starting point in 1 hour 40 minutes. If the speed of the stream is 2 km/hr, find the speed of the boat in still water.

Explanation

To solve the problem, we need to find the speed of the boat in still water. Let's denote the speed of the boat in still water as \( x \) km/hr. The speed of the stream is given as \( 2 \) km/hr.

### Step 1: Determine the effective speeds
When the boat is going downstream, the effective speed of the boat is the sum of the speed of the boat and the speed of the stream:
\[ \text{Speed downstream} = x + 2 \text{ km/hr} \]
When the boat is going upstream, the effective speed of the boat is the speed of the boat minus the speed of the stream:
...