Practice Pakistan questions with answers and explanations.
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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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To convert km/h to m/s, multiply by 5/18.
Thus, 54 × 5/18 = 15 m/s.
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The net rate is 1/10 - 1/15 = 1/30 tank per hour.
Therefore, the tank fills in 30 hours.
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To convert m/s to km/h, multiply by 18/5.
Thus, 20 × 18/5 = 72 km/h.
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The net hourly rate is 1/4 - 1/12.
This equals 2/12 = 1/6.
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Time equals distance divided by speed.
Thus, 12 ÷ 4 = 3 hours.
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Three taps together have three times the rate of one tap.
One tap therefore takes 3 × 6 = 18 hours.
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Their combined daily rate is 1/10 + 1/15 = 1/6.
Therefore, they complete the job in 6 days.
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B's rate is 1/8 - 1/12 = 1/24.
Therefore, B alone needs 24 days.
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Worker-days remain constant for the same job.
Thus, 15 × 20 ÷ 12 = 25 workers.
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Twice the efficiency means twice the daily work rate.
Therefore, A takes half of 18 days, which is 9 days.
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In 5 days, A completes 5/20 = 1/4 of the job.
Therefore, 3/4 remains.
