$\"\"$

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Oil tank leak from the tank at a rate of $\"\"$ liters per hour.

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The time interval is $\"\"$ hours.

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The five time intervals are $\"\"$ and $\"\"$ .

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Observe the table.

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The function is an decreasing function with in the time interval $\"\"$ .

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Upper estimation is the approximation by taking left endpoints with subintervals $\"\"$ and lower estimation is approximation by taking the right end points subintervals $\"\"$ .

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Width of the interval is $\"\"$ .

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Determine the left end approximation.

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Left end points are $\"\"$ and $\"\"$ .

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$\"\"$ .

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Substitute all corresponding rates from the table.

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$\"\"$

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Oil leaked from the tank in 10 hours by left end approximation is $\"\"$ lit.

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Therefore, upper estimation is $\"\"$ lit.

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Determine the right end approximation.

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Right end points are $\"\"$ and $\"\"$ .

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$\"\"$

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Substitute all corresponding rates from the table.

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$\"\"$

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Oil leaked from the tank in 10 hours by left end approximation is $\"\"$ lit.

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Therefore, lower estimation is $\"\"$ lit.

\

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Upper estimation is $\"\"$ lit.

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Lower estimation is $\"\"$ lit.