What is the sixth number in the series: 3, 6, 12, 24? 06/03/2020 – by Mod_GuideK 0 What is the sixth number in the series: 3, 6, 12, 24? A. 48 B. 30 C. 90 D. 96 SHOW ANSWERSCorrect Answer: D Explanation/Reference: Download Printable PDF. VALID exam to help you PASS.