<PRE><B>Question 36552</B>
The sum of a geometric series is 57232. The common ratio is 2 and the last term is 28672. What is the first term?
FORMULA FOR N TH TERM IS ....
TN=A*R^(N-1)..HENCE
28672=A*2^(N-1).......................I
FORMULA FOR SUM IS 
SN=A*{R^N - 1 }/(R-1)...HENCE	
57232 = A*(2^N-1)/(2-1)=A*(2^N-1)....................II	
EQN.II/EQN.I...	
57232/28672=A*(2^N -1)/{A*2^(N-1)}=(2^N -1)/2^(N-1)	
57232/28672=2^N/2^(N-1) - 1/2^(N-1)=2-1/2^(N-1)	
1/2^(N-1)=2-57232/28672=(57344-57232)/28672=112/28672	
2^(N-1)=28672/112=256=2^7	
N-1=7….OR……N=8…SUBSTITUTING IN EQN.I…	
28672=A*2^(8-1)=256A…..OR…..A = 28672/256=112</PRE>