document.write( "Question 1022028: Find the sum of the first 10 terms of geometric series starting at 10 and decreasing by a factor of 2 each time?
\n" ); document.write( "A 5 - 5/2^8
\n" ); document.write( "B 10 - 5/2^8
\n" ); document.write( "C 15 - 5/2^8
\n" ); document.write( "D 20 - 5/2^8
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Algebra.Com's Answer #637709 by rothauserc(4718)\"\" \"About 
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the sum of a geometric series is Sn = a(1 - r^n) / (1 - r) where a is the first term, r is the common ratio, and n is n consecutive terms
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\n" ); document.write( "S10 = 10(1 - (1/2)^10) / ( 1 - (1/2))
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\n" ); document.write( "S10 = 10(1 - (1/(2^10))) / (1/2)
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\n" ); document.write( "divide by 1/2 means multiply by 2
\n" ); document.write( "S10 = 20(1 - (1 /2^10)
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\n" ); document.write( "20 = 2^2 * 5
\n" ); document.write( "S10 = 20 - (((2^2)*5)/ 2^10)
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\n" ); document.write( "S10 = 20 - (5 / 2^8)
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\n" ); document.write( "Answer is D
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