HELP I ONLY HAVE 16 MIN LEFT

Three resistors are connected in parallel.
Their values are 50 ohms,75 ohms and 150 ohms.
Calculate the total resistance (RT) ?

$R_1 = 50 ~Ohms\\ R_2 = 75 ~Ohms\\ R_3 = 150~ Ohms$

$\begin{array}{|rcll|} \hline \frac{1}{R_T} &=& \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} \\\\ \frac{1}{R_T} &=& \frac{1}{50} + \frac{1}{75} + \frac{1}{150} \\ \frac{1}{R_T} &=& 0.02 + 0.01333333333 + 0.00666666667 \\ \frac{1}{R_T} &=& 0.04 \\ R_T &=& \frac{1}{0.04} \\ R_T &=& 25~Ohms \\ \hline \end{array}$