$\"\"$ Exponential growth and Decay model :

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If $\"\"$ is a differentiable function of $\"\"$ such that $\"\"$ and $\"\"$ for some constant $\"\"$ , then $\"\"$ .

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$\"\"$ is the initial value of $\"\"$ and $\"\"$ is the propotional constant.

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Exponential growth occurs when $\"\"$ , and exponential decay occurs when $\"\"$ .

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$\"\"$

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Find value of $\"\"$ .

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$\"\"$

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The half-life of radioactive radium is $\"\"$ .

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Since the half life of radioactive radium, the value of $\"\"$ is $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$ .

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Substitute $\"\"$ in $\"\"$ .

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$\"\"$ . $\"\"$

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Find the radioactive radium initially.

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$\"\"$

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Substitute $\"\"$ in the above equation.

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$\"\"$

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Find the radioactive radium after $\"\"$ .

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$\"\"$

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Substitute $\"\"$ in the above equation.

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$\"\"$

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Find the percent of a radioactive radium at present with respect to after $\"\"$ .

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$\"\"$

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Percent of a radioactive radium at present with respect to after $\"\"$ is $\"\"$ .

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$\"\"$

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Percent of a radioactive radium at present with respect to after $\"\"$ is $\"\"$ .