In a 100 m race, A can beat B by 25 m and B can beat C by 4 m. In the same race, A can beat C by:

$$\eqalign{ & A:B = 100:75 \cr & B:C = 100:96 \cr & \therefore A:C = {\frac{A}{B} \times \frac{B}{C}} \cr & = {\frac{{100}}{{75}} \times \frac{{100}}{{96}}} \cr & = \frac{{100}}{{72}} \cr & 100:72 \cr & \therefore A\,\text{beats}\,C\,by \cr & = \left( {100 - 72} \right)m \cr & = 28\,m \cr} $$