If the probability that the random variable $\mathrm{X}$ takes values $x$ is given by $\mathrm{P}(\mathrm{X}=x)=\mathrm{k}(x+1) 3^{-x}, x=0,1,2,3, \ldots$, where $\mathrm{k}$ is a constant, then $\mathrm{P}(\mathrm{X} \geq 2)$ is equal to :

Question

If the probability that the random variable $\mathrm{X}$ takes values $x$ is given by

$\mathrm{P}(\mathrm{X}=x)=\mathrm{k}(x+1) 3^{-x}, x=0,1,2,3, \ldots$, where $\mathrm{k}$ is a constant, then $\mathrm{P}(\mathrm{X} \geq 2)$ is equal to :