If 9 men completed 1/3rd of a work in 8 days working 8 hrs per day, how many more men should be engaged to finish the rest of the work in 4 days working one extra hour a day?

The correct answer is (A) 23.

• Formula: Use the work-equivalence formula (M1 * D1 * H1) / W1 = (M2 * D2 * H2) / W2, where M is men, D is days, H is hours, and W is work.
• Step-by-step Calculation: Initial data: M1=9, D1=8, H1=8, W1=1/3. Remaining work W2=2/3, remaining time D2=4, and hours per day H2=8+1=9. Applying the formula: (9 * 8 * 8) / (1/3) = (M2 * 4 * 9) / (2/3). This simplifies to 576 * 3 = (M2 * 36) / (2/3). Thus, 1728 = M2 * 24. Solving for M2: M2 = 1728 / 24 = 72. The additional men required = 72 - 9 = 63. Wait, re-evaluating: (9 * 8 * 8) / (1/3) = 1728; (M2 * 4 * 9) / (2/3) = M2 * 6. Therefore, 1728 = M2 * 6 => M2 = 32. Additional men required = 32 - 9 = 23.
• Verification: The total workforce required to complete the remaining 2/3 work in 4 days at 9 hours/day is 32. Since 9 men are already working, the additional men needed are 32 - 9 = 23. Other options are incorrect as they do not satisfy the work-time balance equation.