Govt Exams
Rate = 1/12 + 1/15 - 1/20 = (5+4-3)/60 = 6/60 = 1/10. Time = 10 hours.
Let A's cost = x. B's cost = 1.2x. C's cost = 1.2x × 1.25 = 1.5x = 7500. x = 5000.
Work is proportional to number of men. If work increases by 50%, men needed = M × 1.5 = 1.5M.
Downstream speed = 12 + 3 = 15 km/h. Upstream speed = 12 - 3 = 9 km/h. Time = 90/15 + 90/9 = 6 + 10 = 16 hours. Hmm, should be 16 not 15. Let me verify: 90/15 = 6, 90/9 = 10. Total = 16 hours.
SI = (5000 × 8 × 2)/100 = 800. CI = 5000(1.08)^2 - 5000 = 5832 - 5000 = 832. Difference = 832 - 800 = 32.
A's rate : B's rate = 3:2. Let A's rate = 3x, B's rate = 2x. Combined = 5x = 1/10. So x = 1/50. A's rate = 3/50, time = 50/3 ≈ 16.67 days.
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.
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.
Savings = 100 - 25 - 30 = 45%. If 45% = 9000, then 100% = 9000 × 100/45 = 20,000.
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.