Question
Download Solution PDFThe first term of a GP is 27 and its 8th term is 1/81. Find the sum of its first 10 terms ?
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFCONCEPT:
Let us suppose a be the first term and r be the common ratio of a GP. Then the general term of a GP is given by:
The sum of n terms of a GP with first term ‘a’ and common ratio ‘r’ is given by:
CALCULATION:
Given: The first term of a GP is 27 and its 8th term is 1/81.
Let a be the first term and r be the common difference.
i.e a = 27
As we know that, the general term of a GP is given by:
⇒ a8 = a ⋅ r7 = 27 ⋅ r7 =
⇒ r = 1/3
As we know that,
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