Simplifying, $ S_15 = \frac152 (10 + 42) = \frac152 \times 52 = 15 \times 26 = 390 $. - AMAZONAWS

📅 March 11, 2026 👤 scraface

Mar 11, 2026

$Simplifying, $ S_{15} = \frac{15}{2} (10 + 42) = \frac{15}{2} \times 52 = 15 \times 26 = 390 $.$