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If an initial quantity $\"\"$ continuous decays at an exponential rate $\"\"$ , then the final amount $\"\"$ after a time $\"\"$ is given by the following formula $\"\"$ . $\"\"$

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Starting uranium weight is $\"\"$ grams.

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Since amount of time it takes for half of the atoms of the substance to disintegrate, $\"\"$ grams.

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Substitute $\"\"$ grams, $\"\"$ grams and $\"\"$ in $\"\"$ .

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$\"\"$

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Apply logarithm on each side.

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$\"\"$

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$\"\"$ .

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$\"\"$

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(a)

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Find uranium-235 will remain after $\"\"$ million years.

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Substitute $\"\"$ , $\"\"$ and $\"\"$ in $\"\"$ .

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$\"\"$

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$\"\"$ grams.

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Uranium-235 will remain after $\"\"$ million years is $\"\"$ grams.

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$\"\"$

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(b)

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Find uranium-235 will remain after $\"\"$ million years.

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Substitute $\"\"$ , $\"\"$ and $\"\"$ in $\"\"$ .

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$\"\"$

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$\"\"$ grams.

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Uranium-235 will remain after $\"\"$ million years is $\"\"$ grams.

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$\"\"$

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(a)

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Uranium-235 will remain after $\"\"$ million years is $\"\"$ grams.

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(b)

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Uranium-235 will remain after $\"\"$ million years is $\"\"$ grams.