Answer
Second-order in X, 0.5-order in Y, first-order in Z
Overall order= 3.5
Work Step by Step
Since $[X]$ is raised to the 2nd power, the reaction is second-order in X.
$[Y]$ is raised to the $\frac{1}{2}$ power, so the reaction is 0.5-order in Y.
$[Z]$ is raised to the first power, so the reaction is first-order in Z.
Overall order= Sum of the orders for all substances=2+0.5+1=3.5