SOLUTION: the 12th term of an A.P is -41. given that the first term is 3,find the 20th term

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Question 1147255: the 12th term of an A.P is -41. given that the first term is 3,find the 20th term
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39628) About Me  (Show Source):
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the 12th term of an A.P is -41. given that the first term is 3,
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Common Difference, d

3%2B%2812-1%29d=-41-----solve for d.

General term is 3-%28n-1%29%2A4.
n is index of a term.

Answer by ikleyn(52866) About Me  (Show Source):
You can put this solution on YOUR website!
.

The distance between a%5B1%5D and a%5B12%5D is given as 41+3 = 44.


There are 11 gaps between these terms, each gap is of the same length, equal to the modulus of the common difference.


So, the gap is 44%2F11 = 4 units, and the common difference is  -4 units.


Thus the 20-th term is  3 + 19*(-4) = -73.      ANSWER