A geometric sequence has first term 1 and common ratio 3. What is the 4th term?
Answer and explanation
Correct answer: D. 27
- Step 1: a_n = a_1 q^(n-1).
- Step 2: a_4 = 1 x 3^3 = 27.
Answer
27.
Why not the others: 81 is the next term, one step too far; the other values treat the sequence as arithmetic or multiply by n.
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