- #1

lwelch70

- 23

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**1. Half life of a radioactive substance is 13 days. How long for 400 grams to decay to 300 grams? Solve algebraically and show all work. Give both exact answers and the answer rounded to 4 decimal places.**

So I manipulated (1/2)A

_{0}=A

_{0}e

^{13K}to obtain K = ln(1/2)/13

Where do I go from here?