2026 · Q15
12 men working 8 hours a day can completely build a wall of length 100 m, breadth 20 cm and height 5 m in 10 days. How many days will 16 men working 10 hours a day require to build a wall of length 200 m, breadth 60 cm and height 5 m?
Elementary MathematicsTime and Work
- A18
- B24
- C27
- D36
Explanation
Work is proportional to (men×hours×days)/volume. The first wall has volume 100×0.2×5=100 m³ built in 12×8×10=960 man-hours, i.e. 9.6 man-hours per m³. The second wall has volume 200×0.6×5=600 m³, needing 5760 man-hours; at 16×10=160 man-hours per day this takes 36 days, option D. Forgetting to convert breadth from cm to m is the usual slip.