1) Actual diameter: 4 divided by 1/200=800 cm = 8m, circumference: 3. 14x8 = 25. 12m, radius: 8 divided by 2 = 4m, and area: 3./kloc-0.

2) Actual distance between the two places: 3.6 divided by1/2000000 = 7200000 cm = 72 km, time: 72 divided by 30=2.4 hours,

2.4 hours =2 hours and 24 minutes, 8: 00 +2: 24 = 10: 24.

3) Using the knowledge of inverse proportion, the total workload remains unchanged, assuming that X people are added, (40+x) x (12-2) = 40x12, and the solution is x=8.