SOLUTION: Find the sum of the first 20 terms of the arithmetic series with T1= 31 and T20=109
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Question 1085419: Find the sum of the first 20 terms of the arithmetic series with T1= 31 and T20=109
Answer by ikleyn(52803) (Show Source): You can put this solution on YOUR website!
.
= = = = 140*10 = 1400.
See introductory lessons on arithmetic progressions in this site:
- Arithmetic progressions
- The proofs of the formulas for arithmetic progressions
- Problems on arithmetic progressions
- Word problems on arithmetic progressions
- Solved problems on arithmetic progressions
Also, you have this free of charge online textbook in ALGEBRA-II in this site
- ALGEBRA-II - YOUR ONLINE TEXTBOOK.
The referred lessons are the part of this online textbook under the topic "Arithmetic progressions".
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