The rate expression for the reaction $X (g) + 2Y (g) → 3Z (g)$ is

The rate expression for the reaction $X (g) + 2Y (g) → 3Z (g)$ is

$\text{rate} = k[X]^0 [Y]^2$

By which factor will the rate of reaction increase when the concentrations of X and Y are both increased by a factor of 3?