In an arithmetic sequence the third term is 11 and the seventh term is 27. What is the 15th term?
Answer and explanation
Correct answer: A. 59
- Step 1: Seventh term - third term = 4d, so 4d = 27 - 11 = 16 and d = 4. Step 2. First term a = 11 - 2 x 4 = 3. Step 3. a_15 = 3 + 14 x 4 = 59. Answer: 59. Why not the others: 63: That is the next term, the 16th. 55: That is the previous term, the 14th. 23: That adds 1 for each step instead of the common difference.
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