MathematicsMedium178×since 2002Q5299The sum of the first 20 terms of the series 1+32+74+158+3116+...,1 + {3 \over 2} + {7 \over 4} + {{15} \over 8} + {{31} \over {16}} + ...,1+23+47+815+1631+..., is :A38+121938 + {1 \over {{2^{19}}}}38+2191B38+122038 + {1 \over {{2^{20}}}}38+2201C39+122039 + {1 \over {{2^{20}}}}39+2201D39+121939 + {1 \over {{2^{19}}}}39+2191Check answerSkip