Answer
$\dfrac {3}{2^{2}}+\dfrac {3^{2}}{2^{3}}+\dfrac {3^{3}}{2^{4}}+\dots + \dfrac {3^{50}}{2^{51}}$
Work Step by Step
$\sum ^{50}_{k=1}\dfrac {3^{k}}{2^{k+1}}=\dfrac {3^{1}}{2^{1+1}}+\dfrac {3^{2}}{2^{2+1}}+\dfrac {3^{3}}{2^{3+1}}+\ldots +\dfrac {3^{50}}{2^{50+1}}=\dfrac {3}{2^{2}}+\dfrac {3^{2}}{2^{3}}+\dfrac {3^{3}}{2^{4}}+\dots + \dfrac {3^{50}}{2^{51}}$
