Answer:
The system has 35% of B.
Explanation:
Number of A atoms = 65
Number of B atoms = 35
Mass of atom A = M
Mass of atom B = 18M
Total atoms of the system = 65 + 35= 100
Total of atoms of B = 35
The percentage of B is the system ;
[tex]=\frac{35M}{100M}\times 100=35\%[/tex]
The system has 35% of B.