Question

The speed of a boat along the stream is 12 km/hr and speed of the boat against the stream is 6 km/hr, how much time will the boat take to cross a distance of 27 km in still water?

• A. 2 hrs
• B. 1 hr
• C. 5hrs
• D. 3hrs

Answer 1

Answer:

D. 3hrs

Given:

Downstream speed of the boat = 12 km/hr

Upstream speed of the boat = 6 km/hr

Formula Used:

Speed of boat in still water = Speed of (Upstream+Downstream)/2

Calculation:

According to the question,

Speed of the boat in still water = $\frac{(12 + 6)}{2}$

⇒ 9 $\frac{km}{hr}$

Now, required time to cross 27 km in still water = $\frac{27}{9}$

⇒ 3 hours

∴ The required time is 3 hours.