Question 1197285
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a = 18 = first term


Assuming this sequence is geometric, then,
r = common ratio
r = (term2)/(term1)
r = 12/18
r = 2/3


Or
r = (term3)/(term2)
r = 8/12
r = 2/3


2/3 = 0.667 approximately


Since -1 < r < 1 is true, this means the infinitely many terms of this sequence add to some fixed value S
S = a/(1-r)
S = 18/(1-2/3)
S = 18/(3/3-2/3)
S = 18/(1/3)
S = 18*3/1
S = 54


Answer: 54
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