Explanation:

- Total Work: The contract is to be completed in 48 days with 125 men working 9 hours each day.

- Hence, total work = 125 men × 9 hours/day × 48 days.

- Work Done Till Now: After 28 days, 3/7 of the work is completed.

- So, work left = 4/7 of the total work.

- Current Resources: 125 men, 9 hours/day, for 20 more days.

- Adjustment: Each man will now work 10 hours/day.

- New Condition: To complete the work in the remaining 20 days.

- Calculation: Let's determine additional men.

- New total work by current men = 125 men × 10 hours/day × 20 days.

- Solution: After setting the equation with above details, you need additional men.

- Final Answer: Using the calculation, 85 additional men are needed.

So, the correct option is Option 3: 85.

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