What is the sum of the first 5 terms of the geometric sequence with first term 1 and common ratio 4?
Answer and explanation
Correct answer: D. 341
- Step 1: S_n = a (r^n - 1)/(r - 1). Step 2. = 1 (1024 - 1)/3 = 341. Answer: 341. Why not the others: 1024: That is the (n + 1)th term, not the sum. 256: That is the nth term, not the sum. 340: That leaves out the first term.
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