Discussion Forum

While covering a distance of 24 km, a man noticed that after walking for 1 hour and 40 minutes, the distance covered by him was $\frac{5}{7}$ of the remaining distance. What was his speed in metres per second ?

Answer:

Explanation:

Let the speed be $x$ km/hr.

Then, distance covered in 1 hr. 40 min. i.e. $1\frac{2}{3}$ hrs $=\frac{5x}{3}$ km

Remaining distance $=\left(24-\frac{5x}{3}\right)$ km

$\frac{5x}{3}=\frac{5}{7}\left(24-\frac{5x}{3}\right)$

$\Leftrightarrow\frac{5x}{3}=\frac{5}{7}\left(\frac{72-5x}{3}\right)$

$\Leftrightarrow 7x=72-5x$

Hence, speed = 6 km/hr $=\left(6\times\frac{5}{18}\right)$ m/sec

$=\frac{5}{3}$ m/sec $=1\frac{2}{3}$ m/sec.