In a 100 metres race, Kamal defeats Bimal by 5 seconds. If the speed of Kamal is 18 kmph, then the speed of Bimal is :

Answer: Option C

Time taken by Kamal :
$$=\frac{100}{18\times \frac{5}{18}}=20\sec$$
Time taken by Bimal :
$$\begin{array}{rl}& =20+5\\ & =25\sec \end{array}$$
Speed of Bimal :
$$\begin{array}{rl}& =\frac{100}{25}\times \frac{18}{5}\\ & =14.4\text{ kmph}\end{array}$$