A works three times as fast as B. Together they finish in 8 days. How long does A take alone?
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Let B's rate be 1 unit and A's 3 units, total 4 units.
A alone takes 8 × 4/3 = 32/3 days.
Practice Pakistan questions with answers and explanations.
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Let B's rate be 1 unit and A's 3 units, total 4 units.
A alone takes 8 × 4/3 = 32/3 days.
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The machine produces 60/5 = 12 units per hour.
In 8 hours it produces 12 × 8 = 96 units.
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Their combined rate is 1/12 + 1/18 + 1/36 = 1/6.
Therefore, they finish in 6 days.
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If 40% takes 12 days, 10% takes 3 days.
The remaining 60% takes 18 days.
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Let B's rate be 2 units and A's rate be 3 units, total 5 units.
If 5 units finish in 6 days, B alone takes 6 × 5/2 = 15 days.
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The leak rate is 1/9 - 1/12 = 1/36 tank per hour.
Thus, the leak alone empties the tank in 36 hours.
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Their daily rate is 1/16 + 1/24 = 5/48.
In 4 days they do 5/12, so 7/12 remains.
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Speed equals distance divided by time.
Thus, 180 ÷ 3 = 60 km/h.
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The pipe fills 1/6 of the tank per hour.
In 2 hours it fills 2/6 = 1/3.
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Distance equals speed multiplied by time.
Thus, 72 × 2.5 = 180 km.
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Their combined rate is 1/8 + 1/12 = 5/24 tank per hour.
Time is 24/5 = 4.8 hours.
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The net rate is 1/10 - 1/15 = 1/30 tank per hour.
Therefore, the tank fills in 30 hours.