.
+ = + = = 280. (1)
+ = + = = 4375. (2)
Now divide eq(2) by eq(1) (both sides). After canceling common multipliers, you will get
= = 15.625.
Hence, r = = 2.5.
Thus the common difference is r = 2.5.
The equation (1) the becomes
= 280, which implies = = 32.
Answer. The first term is 32. The common difference is 2.5.
Solved.
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There is a bunch of lessons on geometric progressions in this site
- Geometric progressions
- The proofs of the formulas for geometric progressions
- Problems on geometric progressions
- Word problems on geometric progressions
- One characteristic property of geometric progressions
- Solved problems on geometric progressions
- Fresh, sweet and crispy problem on arithmetic and geometric progressions
- Mathematical induction and geometric progressions
- Mathematical induction for sequences other than arithmetic or geometric
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- ALGEBRA-II - YOUR ONLINE TEXTBOOK.
The referred lessons are the part of this online textbook under the topic "Geometric progressions".
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