A 400-mg sample of technetium-99m is used for a diagnostic test. If technetium-99m has an effective half-life of 4.8 hours, how much of the technetium-99m remains 72 hours after the test?
Express your answer to two significant figures and include the appropriate units.

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Which of two curves exhibits exponential growth

Why is it important for scientists to review and repeat the work of other scientists? 1.a scientific theory must be tested three times before it is proven. 2.the scientific method only applies to repeated experiments. 3.an experiment may have had errors that the scientists didn't recognize. 4.the results of individual scientists may be influenced by bias. 5.an experiment must be performed twice before the data can be analyzed.