If 100 atoms of element X contains 70 atoms of <sup>9</sup>X and 30 atoms of <sup>11</sup>X, calculate the relative atomic mass of X

If 100 atoms of element X contains 70 atoms of 9X and 30 atoms of 11X, calculate the relative atomic mass of X

If 100 atoms of element X contains 70 atoms of ⁹X and 30 atoms of ¹¹X, calculate the relative atomic mass of X

The correct answer is A. 9.6

No explanation given