Mathematics - Probability Question with Solution | TestHub

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