Question 1173921
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Note: Both formal algebraic solutions from other tutors are fine; but there is a faster path to the answer.<br>
The sum of 15 terms of an arithmetic series is 15 times the middle term.<br>
In a series with 15 terms, the middle term is the 8th term.<br>
With 5th term 4 and common difference 3, the 8th term is 4+3(3) = 4+9 = 13.<br>
ANSWER: The sum is 15(13) = 195.<br>