Let XXX be a random variable with P(X=k)=12kP(X = k) = \frac{1}{2^k}P(X=k)=2k1 for k=1,2,3,…k = 1, 2, 3, \ldotsk=1,2,3,…. What is P(X>3)P(X > 3)P(X>3)?
18\frac{1}{8}81
116\frac{1}{16}161
14\frac{1}{4}41
12\frac{1}{2}21