10 workers can build a wall in 28 days. How many days will 20 workers take to build the same wall, working at the same rate?

💡 Solution & Explanation

The total work is 10 × 28 = 280 worker-days. More workers means fewer days, so divide: 280 ÷ 20 = 14 days. Multiplying instead (56 days) would mean more workers take longer, which cannot be right.