Multiple choice general knowledge If it took 8 men 10 hours to build a wall, how long would it take 4 men to build it? 20 hrs 10 hrs 18 none of these 22 Reveal answer Fill a bubble to check yourself A Correct answer Explanation This is an inverse proportion problem involving man-hours. If 8 men take 10 hours, the total work is 8 times 10, which equals 80 man-hours. Therefore, 4 men will take 80 divided by 4, resulting in 20 hours.