The first term of an arithmetic sequence is 3 and the common difference is 5. What is the 15th term?
Answer and explanation
Correct answer: C. 73
- Step 1: a_n = a_1 + (n - 1)d.
- Step 2: a_15 = 3 + 14 x 5 = 73.
Answer
73.
Why not the others: 78 uses n instead of n - 1; 68 uses n - 2; the second value treats the sequence as geometric.
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