Rate A = 1/20, B = 1/30. In 6 hours: filled = 6(1/20 + 1/30) = 6(5/60) = 30/60 = 1/2. Remaining = 1/2. Time for A alone = (1/2)/(1/20) = 10/2 = 10 hours. This doesn't match. Recalculate: 6(1/20 + 1/30) = 6((3+2)/60) = 6(5/60) = 30/60 = 1/2. A needs 1/2 ÷ 1/20 = 10 hours. Not in options. Let me reconsider: 6 × (1/20 + 1/30). LCM(20,30)=60. 6 × (3/60 + 2/60) = 6 × 5/60 = 30/60 = 1/2. Remaining = 1/2. Time = (1/2) × 20 = 10 hours.

CI for 2 years = 10000(1.08)² - 10000 = 10000(1.1664) - 10000 = 1664. Average annual interest = 1664/2 = 832. Wait, that's option C. Let me verify: A = 10000 × 1.08² = 11664. CI = 1664. Average per year = 1664/2 = 832. But option C is 832. Recalculating interest earned = 11664 - 10000 = 1664. Average = 832. But maybe question asks average including principal growth: (1664)/2 = 832 or using different method: Year 1 interest = 800, Year 2 interest = 864. Average = 832. So answer should be C.

Sum of 5 numbers = 48 × 5 = 240. Sum of 4 numbers = 40 + 45 + 50 + 55 = 190. Fifth number = 240 - 190 = 50.

Let current speed = c. Upstream speed = 15 - c, downstream = 15 + c. Distance = 4(15-c) = 2(15+c). 60 - 4c = 30 + 2c. 30 = 6c. c = 5 km/h.

Total income of 4 = 45000 × 4 = 180000. After 5th employee: 180000 + 55000 = 235000. New average = 235000 / 5 = 47000.

Let milk = 3x, water = 2x. Total = 5x. After removing 10L: milk = 3x - 6, water = 2x - 4. After adding 10L milk: milk = 3x + 4, water = 2x - 4. New ratio: (3x+4)/(2x-4) = 4/1. So 3x + 4 = 8x - 16. 20 = 5x. x = 4. Original milk = 3 × 4 = 12 liters. Hmm, not matching. Recheck: (3x+4)/(2x-4) = 4. 3x + 4 = 4(2x - 4) = 8x - 16. -5x = -20. x = 4. Milk = 12L. But this isn't an option. Let me recalculate removed amount: ratio is 3:2, so in 10L removed: milk = 6L, water = 4L.

For 8 consecutive even numbers with average 15: Let smallest = x. Numbers are x, x+2, x+4, ..., x+14. Average = (x + x+14)/2 = x+7 = 15. So x = 8. But average of even numbers can't be odd. Question error - assuming average is 14: x+7 = 14, x = 7 (odd). If average is 16: x+7 = 16, x = 9 (odd). Reconsidering: average of 8 numbers = 15 means sum = 120. If x is smallest: x + (x+2) + ... + (x+14) = 8x + 56 = 120. So 8x = 64, x = 8. But 8 is option D. Verification: 8,10,12,14,16,18,20,22 average = 136/8 = 17 ≠ 15. Problem has inconsistency. Likely intended average = 9: 8x + 56 = 72, x = 2.

For equal distances, average speed = 3/(1/40 + 1/50 + 1/60) = 3/((3+2.4+2)/120) = 3/(7.4/120) = 360/7.4 = 48.65 ≈ 49.09 km/h. Using LCD: 3/((15+12+10)/600) = 1800/37 ≈ 48.65 km/h.

Total height of 5 = 165 × 5 = 825 cm. After adding 180 cm: 825 + 180 = 1005 cm. New average = 1005 / 6 = 167.5 cm.

CP = 100 × 50 = 5000. SP of 60 at 20% profit = 60 × 50 × 1.2 = 3600. SP of 40 at 10% loss = 40 × 50 × 0.9 = 1800. Total SP = 5400. Profit = 400. Profit% = (400/5000) × 100 = 8%.