Geometric Progressions — O/L Mathematics

How do I practise Geometric Progressions?

1 question with a worked solution

1. The first term of a geometric progression is 5 and the common ratio is 2. What is the 7th term of this progression?
   1. A) 256
   2. B) 160
   3. C) 320
   4. D) 640
   Check my answer

   Correct answer: C) 320

   The nth term of a geometric progression is T_n = a·r^n-1. Here, a = 5, r = 2, n = 7: T₇ = 5 × 2^7-1 = 5 × 2⁶ = 5 × 64 = 320.

   Show worked solution

   Step 1: Formula for nth term of GP: T_n = a·r^n-1. Step 2: Identify parameters: a = 5, r = 2, n = 7. Step 3: Calculate power: 2^{7 - 1} = 2⁶ = 64. Step 4: Multiply by first term: 5 × 64 = 320. Answer: 320.
   Modelled on: the O/L Mathematics examination pattern

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Where does Geometric Progressions fit in the syllabus?

Grade 11 · Term 2