Current Electricity

In an experiment to determine the temperature coefficient of resistance of a conductor, a coil of wire $X$ is immersed in a liquid. It is heated by an external agent. A meter bridge set up is used to determine resistance of the coil $X$ at different temperatures. The balancing points measured at temperatures $t_1=0^{\circ} \mathrm{C}$ and $t_2=100^{\circ} \mathrm{C}$ are 50 cm and 60 cm respectively. If the standard resistance taken out is $S=4 \Omega$ in both trials, the temperature coefficient of the coil is