Question

A man rows upstream $13km$ and down stream $28km$ taking $5$ hours each time. What is the speed of the current?

• A. $1.5kmp.h.$
• B. $3kmp.h.$
• C. $1kmp.h.$
• D. $5kmp.h.$

Answer 1

The correct option is A $1.5kmp.h.$

The man takes 5 hours for 13 k upstream rowing another 5 hours for 28 km downstream rowing.

$\therefore$ speed of upstream $=\frac{13}{5}km.hr$ and speed of downstream $=\frac{28}{5}km/hr$

We know, speed of current $=\frac{1}{2}$ ( downstream speed - upstream speed )

$\therefore$ speed of current $=\frac{1}{2}(\frac{28}{5}-\frac{!3}{5})km/hr=1.5km/hr$

$\therefore$ optionA is correct.