Arithmetic Progression
The sum of the first 20 terms of an AP with first term 5 and common difference 3 is
Select the correct option:
Solution
670
- Identify Data: a=5, d=3, n=20.
- Sum Formula: Sn=2n[2a+(n−1)d].
- Substitution:
- S20=220[2(5)+(20−1)(3)]
- S20=10[10+(19)(3)]
- Final Computation:
- S20=10[10+57]=10×67=670.
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About This Question
- Subject
- mathematics
- Chapter
- sequence and series
- Topic
- arithmetic progression
- Difficulty
- Easy
- Year
- 2025
Solution
Correct Answer:
670
- Identify Data: a=5, d=3, n=20.
- Sum Formula: Sn=2n[2a+(n−1)d].
- Substitution:
- S20=220[2(5)+(20−1)(3)]
- S20=10[10+(19)(3)]
- Final Computation:
- S20=10[10+57]=10×67=670.
This easy difficulty mathematics question is from the chapter sequence and series, covering the topic of arithmetic progression. It appeared in the 2025 exam.
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