Question 1085497
k=1, product is 3/2
2--3/4
3--3/8
4--3/16
5--3/32
common denominator is 32, numerator is 93, 93/32,
A
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at 5, it is 46.  At 20, it is 106
at 12, it is 74, at 13, it is 78.  The average term is 76. There are 16 terms, average is 76, total 1216.
D
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a1=8; an=a1*2^(n-1)
for 8th term is is a1(1-2^8)/(1-2)=8*(-255/-1)=8*255=2040
8+16+32+64+128+256+512+1024=2040
C
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Partial sum between 9 and 57, with d=3
There are 17 terms, there is a middle term (the ninth, which is a1+(3*8)=33) so 17 times the average, which is 33=561.
B