Find the sum of the series ∑k=0∞(12)k(13)k\sum_{k=0}^{\infty} (\frac{1}{2})^k (\frac{1}{3})^k∑k=0∞(21)k(31)k.
0.50.50.5
0.60.60.6
1.51.51.5
0.750.750.75