SOLUTION: The first term is -140. Each term is equal to the previous term multiplied by a common ratio. The common ratio is 0.5. what would the term value be for the 20th term?

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Question 1206361: The first term is -140. Each term is equal to the previous term multiplied by a common ratio. The common ratio is 0.5. what would the term value be for the 20th term?
Found 2 solutions by math_tutor2020, greenestamps:
Answer by math_tutor2020(3817) About Me  (Show Source):
You can put this solution on YOUR website!

The sequence is geometric.
a = -140 = first term
r = 0.5 = common ratio

a%5Bn%5D+=+a%2A%28r%29%5E%28n-1%29 = nth term of a geometric sequence, where n is a positive integer (1,2,3,4,...)

a%5Bn%5D+=+-140%2A%280.5%29%5E%28n-1%29

a%5B20%5D+=+-140%2A%280.5%29%5E%2820-1%29

a%5B20%5D+=+-0.00026703 approximately depending how you round it

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


The n-th term is the first term, multiplied by the common ratio (n-1) times.

%28-140%29%280.5%29%5E19 = -0.000267 to 3 significant figures.

The other tutor shows the right answer, but the calculations are not showing correctly... might be a problem with the algebra.com website.

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Oh... now I see his response is displaying correctly....