Practice IBA Mathematics questions with answers and explanations.
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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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In 5 days, A completes 5/20 = 1/4 of the job.
Therefore, 3/4 remains.
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If half the work takes 6 days, the full work takes twice as long.
Thus, the total time is 12 days.
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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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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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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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The pipe fills 1/6 of the tank per hour.
In 2 hours it fills 2/6 = 1/3.
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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.
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The net hourly rate is 1/4 - 1/12.
This equals 2/12 = 1/6.
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Each year, 90% of the previous value remains.
Thus, 50,000 × 0.9² = Rs. 40,500.
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Compound growth gives 20,000 × 1.05².
The result is 22,050.
