A meter bridge setup is shown in the figure. It is used to determine an unknown resistance $R$ using a given resistor of $15\,\Omega$. The galvanometer ($G$) shows null deflection when tapping key is at 43 cm mark from end $A$. If the end correction for end $A$ is 2 cm, then the determined value of $R$ will be $\_\_\_\_\,\Omega$.