Wikipedia has the following current divider rule
$$I_X = \frac{R_T}{R_X + R_T} \times I_T$$
where as certain websites have the following rule:
$$I_X = \frac{R_{total}}{R_X} \times I_T$$
where
$$\frac{1}{R_{total}} = \frac{1}{R_X} + \frac{1}{R_T}$$
for two resistors, this simplifies to
$$R_{total} = \frac{R_X \times R_T}{R_X + R_T}$$
These two rules are equal:
\begin{align}
I_X &= I_T \times \frac{R_{total}}{R_X} \\
&= I_T \times R_{total} \times \frac{1}{R_X} \\
&= I_T \times \frac{R_X \times R_T}{R_X + R_T} \times \frac{1}{R_X} \\
&= I_T \times \frac{R_T}{R_X + R_T}
\end{align}
