100 points! Please answer by explaining it well.

Find the volume of the composite solid.

Please list all steps.

And please answer as soon as possible.

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The half-life of a certain material is 0.002 second. approximately how much of a 14-gram sample will be left after 0.004 second? a. 12 grams b. 3.5 grams c. 0.06 gram d. 7 grams