In a 400 metre race, A runs at a speed of 16 m/sec. If A gives B a start of 15 metres and still beats him by 10 sec, then what is the speed of B?

\[\begin{array}{*{20}{c}} {}&{\text{A}}&{\text{B}} \\ {{\text{Distance}} \to }&{400}&{385} \end{array}\]
$$\eqalign{ & \frac{{400}}{{\text{A}}} = \frac{{385}}{{\text{B}}} - 10 \cr & \frac{{400}}{{16}} = \frac{{385}}{{\text{B}}} - 10 \cr & 25 + 10 = \frac{{385}}{{\text{B}}} \cr & {\text{B}} = 11 \cr & {\text{Speed of B}} = 11{\text{ m/s}} \cr} $$