Final answer:
The 30th term of the arithmetic sequence 210, 215, 220,... is calculated using the formula a_n = a_1 + (n-1)*d and is found to be 355. None of the options provided in the question match this answer.
Step-by-step explanation:
To determine the 30th term of the sequence 210, 215, 220,..., we identify this as an arithmetic sequence where each term increases by a common difference from the previous term. In this case, the common difference (d) is +5. The formula for the nth term of an arithmetic sequence is a_n = a_1 + (n-1)*d, where a_1 is the first term, and n is the term number. Here, a_1 is 210, n is 30, and d is 5.
Let's apply the formula:
a_30 = 210 + (30-1)*5
a_30 = 210 + 29*5
a_30 = 210 + 145
a_30 = 355
Therefore, the 30th term of the sequence is 355, which is not listed in the options presented in the question. There may be a mistake in the provided sequence or the answer choices.