Total distance = train length + platform length = 200 + 400 = 600m. Speed = 600/30 = 20 m/s.

Profit = 1000 - 800 = ₹200. Profit% = (200/800) × 100 = 25%.

Combined rate = 1/6 + 1/8 + 1/12 = (4+3+2)/24 = 9/24 = 3/8. Time = 8/3 = 2.67 days ≈ 2.4 days. Actually 8/3 ≈ 2.67, but closest is 2.4. Let me recalculate: LCM(6,8,12) = 24. Rate = 4/24 + 3/24 + 2/24 = 9/24 = 3/8. Time = 8/3 ≈ 2.67. Answer should be close to this.

Let CP = 100. MP = 150. SP = 150 × 80/100 = 120. Profit = 20. Profit% = 20%.

A = P(1+r/100)^n. 14400 = 12000(1+r/100)^2. 1.2 = (1+r/100)^2. √1.2 ≈ 1.095. r ≈ 9.5%. Closest is 10%.

Relative speed = 40 + 50 = 90 km/h = 25 m/s. Total distance = 150 + 250 = 400m. Time = 400/25 = 16 seconds. Closest option is 18 seconds.

A does 1/3 work in 5 days, so full work in 15 days. B does 2/3 work in 10 days, so full work in 15 days. Combined rate = 1/15 + 1/15 = 2/15. Time = 15/2 = 7.5 days. Wait, let me recalculate B: If 2/3 in 10 days, then 1 in 15 days. So both take 15 days individually. Together: 2/15 per day, so 15/2 = 7.5 days.

Savings = 100 - 25 - 30 = 45%. If 45% = 9000, then 100% = 9000 × 100/45 = 20,000.

In 2 hours (A for 1 hour, then B for 1 hour): Net filling = 1/10 - 1/15 = (3-2)/30 = 1/30. To fill 30/30, we need 60 hours of 2-hour cycles = 30 cycles of 2 hours = 60 hours. Hmm, this doesn't match. Let me recalculate: Each 2-hour cycle = 1/30 filled. 30 cycles needed = 60 hours total. But option is 24. Let me verify the problem setup again with the given options.

CP = 100 × 50 = ₹5000. SP = 80 × 75 + 20 × 40 = 6000 + 800 = ₹6800. Profit = 800. Profit% = 800/5000 × 100 = 16%. Closest is 10% or need to recalculate.