Q63.Let a, ar, ar2 , be an infinite G.P. If ∑∞n=0 arn = 57 and ∑∞n=0 a3r3n = 9747, then a + 18r is equal to (1) 46 (2) 38 (3) 31 (4) 27 is
What This Question Tests
This question requires solving a system of two equations derived from the sum of an infinite geometric progression and the sum of an infinite geometric progression formed by cubes of its terms, to find 'a' and 'r'.
Concepts Tested
Formulas Used
S_∞ = a / (1-r)
S_∞' = a' / (1-r')
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📋 Question Details
- Chapter
- Sequences & Series
- Topic
- Geometric Progression (G.P.)
- Year
- 2024
- Shift
- 09 Apr Shift 2
- Q Number
- Q63
- Type
- MCQ
- NCERT Ref
- Class 11 Mathematics Ch 9: Sequences and Series
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