Answer
$60$
Work Step by Step
We sum from i = low bound to i = high bound.
$(8+4) + (10+4) + (12+4) + (14+4) = 12 + 14 + 16 + 18 = 60$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.