Question

A boat running downstream covers a distance of 16 km in 2 hours while for covering the same distance upstream, it takes 4 hours. What is the speed of the boat in still water?

• A. 4 km/hr
• B. 6 km/hr
• C. 8 km/hr
• D. Data inadequate

Answer 1

Answer: (B)

6 km/hr

Rate downstream $=\left(\frac{16}{2}\right)kmph=8kmph$
Rate upstream $=\left(\frac{16}{4}\right)kmph=4kmph$
$\therefore$ Speed in still water $=\frac{1}{2}(8+4)kmph=6kmph$