The first term of an arithmetic sequence is 10 and the common difference is 3. What is the 20th term?
Answer and explanation
Correct answer: A. 67
- Step 1: a_n = a_1 + (n - 1)d.
- Step 2: a_20 = 10 + 19 x 3 = 67.
Answer
67.
Why not the others: 70 uses n instead of n - 1; 64 uses n - 2; the second value treats the sequence as geometric.
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