Consider the following reaction \( \mathrm{A + B \rightarrow C} \).
The time taken for \( \mathrm{A} \) to become $1/4^{\text{th}}$ of its initial concentration is twice the time taken to become \( \tfrac{1}{2} \) of the same. Also, when the change of concentration of \( \mathrm{B} \) is plotted against time, the resulting graph gives a straight line with a negative slope and a positive intercept on the concentration axis. The overall order of the reaction is ______.