Speed, Distance and Time

$$1\ \frac{km}{h}=\frac{1\ km}{1\ hr}=\frac{1000\ m}{3600\ \sec}$$ Simplify...

$$\frac{5}{18}\ \frac{m}{s}$$

$$\therefore1\ \frac{km}{hr}=\frac{5}{18}\ \frac{m}{s}$$

1 km/h = (1000 m/3600 sec) m/s

Similarly, 1 m/s = (0.001 km/0.0003 hr) km/h

$$\therefore1\ \frac{m}{s}=\frac{18}{5}\ \frac{km}{h}$$

Calculation for Rohit:-

Speed of Rohit: 2 km/h

Time: 3 h

$$\because D=T\times S$$

$$=3\times2$$

$$=6$$

$$\therefore Dista\ nce\ covered\ by\ Rohit\ =\ 6\ km$$

Calculation for Ranjan:-

Speed of Ranjan: 4 km/h

Time: 3 h

$$\because D=S\times T,$$

$$=4\times3$$

$$=12$$

$$\therefore Dista\ nce\ covered\ by\ Ranjan\ =\ 12\ km$$

Conclusion:-

12-6=6

$$\therefore Ranjan\ is\ ahead\ of\ Rohit\ by\ 6\ km.$$