Question 711986: Determine the number of terms in the following arithmetic sequence: 315, 304, 293, ... , 18.
Found 2 solutions by stanbon, MathLover1:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Determine the number of terms in the following arithmetic sequence:
315, 304, 293, ... , 18
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a = 315
d = 304-315 = -11
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Solve for "n":
a(n) = a + (n-1)d
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18 = 315 + (n-1)(-11)
-297 = (n-1)(-11)
n-1 = (-297/-11)
n-1 = 27
n = 28 (# of terms)
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Cheers,
Stan H.
Answer by MathLover1(20850)  (Show Source):
You can put this solution on YOUR website!
as you can see, in the following arithmetic sequence,  ,  ,  , ... ,  , the difference between each term is  (the fixed amount is called the common difference,  )
 ...then next term will be
 ....and so on, up to
To find any term of an arithmetic sequence use formula:
 where  is the first term of the sequence,
 is the common difference,  is the number of the term to find
in your case is given  , , and we found that 
...solve for
 ......plug in given values
 ......the number of terms
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