ExplanationThis is an arithmetic sequence where the difference between successive terms is always +10.
The difference between, for example, \(a_{10}\) and \(a_{11}\), is exactly 10, regardless of the actual values of the two terms. The difference between \(a_{10}\) and \(a_{12}\) is \(10 + 10 = 20\), or \(10 \times 2 = 20\), because there are two “steps,” or terms, to get from \(a_{10}\) to \(a_{12}\). Starting from a10, there is a sequence of 5 terms to get to \(a_{15}\).
Therefore, the difference between \(a_{10}\) and \(a_{15}\) is \(10 \times 5 = 50\).
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