Chemistry

Problem

A mineral presently retains

60\%

of its original

^{40}\text{K}

content. The half-life of

^{40}\text{K}

1.25\times10^{9}\,\text{years}

. The approximate age of the mineral is a)

1.25\times10^{9}\,\text{years}

5.0\times10^{8}\,\text{years}

9.2\times10^{8}\,\text{years}

1.65\times10^{9}\,\text{years}