Q66.The product of three consecutive terms of a G. P. is 512. If 4 is added to each of the first and the second of these terms, the three terms now form an A. P., then the sum of the original three terms of the given G. P. is : (1) 28 (2) 24 (3) 32 (4) 36
What This Question Tests
This question combines properties of Geometric and Arithmetic Progressions. Represent the three consecutive terms of the GP as a/r, a, ar. Use the product condition to find 'a'. Then apply the given modification and the AP condition to find 'r'. Finally, calculate the sum of the original three terms.
Concepts Tested
Formulas Used
Terms of GP: a/r, a, ar
Terms of AP: b-d, b, b+d
Property of AP: 2b = (b-d)+(b+d)
📚 NCERT Sections This Tests
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12.7 The radius of the innermost electron orbit of a hydrogen atom is 5.3×10–11 m. What are the radii of the n = 2 and n =3 orbits?
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📋 Question Details
- Chapter
- Sequences & Series
- Topic
- Geometric Progression (GP) and Arithmetic Progression (AP)
- Year
- 2019
- Shift
- 12 Jan Shift 1
- Q Number
- Q66
- Type
- MCQ
- NCERT Ref
- Class 11 Mathematics Ch 9: Sequences and Series
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