A sample of an element A contains 2 isotopes A⁸16 and A⁸18. If the average atomic mass of the element is 16.2 amu, calculate the percentage of the 2 isotopes in this sample.
a) 81% A⁸16, 19% A⁸18
b) 80% A⁸16, 20% A⁸18
c) 82% A⁸16, 18% A⁸18
d) 83% A⁸16, 17% A⁸18