question_answer

The average atomic mass of a sample of an element X is 16.2 u. What are the percentages of isotopes \[{}_{8}^{16}X\,\,and\,\,{}_{8}^{18}X\] in the sample?

A) Percentage of \[{}_{8}^{16}X=80\] and percentage of \[{}_{8}^{18}X=20\]

B) Percentage of \[{}_{8}^{16}X=70\]and percentage of \[{}_{8}^{18}X=30\]

C) Percentage of \[{}_{8}^{16}X=90\]and percentage of \[{}_{8}^{18}X=10\]

D) Percentage of \[{}_{8}^{16}X=95\]and percentage of \[{}_{8}^{18}X=5\]

E) None of these