PATTERNS, FUR1 2009 VCAA 4 MC The sum of the infinite geometric sequence 96, – 48, 24, –12, 6 . . . is equal to A. `64` B. `66` C. `68` D. `144` E. `192` Show Answers Only `A` Show Worked Solution `text(Sequence is)\ \ \ 96, –48, 24, –12, 6, …` `text(GP where)\ \ \ a` `=96, and` `r` `=t_2/t_1 = (–48)/96 = –1 /2` `text(S)text(ince)\ \ |\ r\ | < 1` `S_∞` `=a/(1-r)` `=96/(1-(-1 /2))` `=64` `=> A`