How many times are there more oxygen atoms in the grain crust than silicon atoms

How many times are there more oxygen atoms in the grain crust than silicon atoms, if their content by mass is 49.5% and 25.7%, respectively?

Given:
ω (O) = 49.5%
ω (Si) = 25.7%

To find:
N (O)? N (Si)

Decision:
1) Let m sample = 100 g;
2) m (O) = ω (O) * m sample / 100% = 49.5% * 100/100% = 49.5 g;
3) n (O) = m (O) / M (O) = 49.5 / 16 = 3.094 mol;
4) N (O) = n (O) * NA = 3.094 * 6.02 * 10 ^ 23 = 18.626 * 10 ^ 23;
5) m (Si) = ω (Si) * m sample / 100% = 25.7% * 100/100% = 25.7 g;
6) n (Si) = m (Si) / M (Si) = 25.7 / 28 = 0.918 mol;
7) N (Si) = n (Si) * NA = 0.918 * 6.02 * 10 ^ 23 = 5.526 * 10 ^ 23;
8) N (O) / N (Si) = 18.626 * 10 ^ 23 / 5.526 * 10 ^ 23 = 3.37.

Answer: The number of O atoms is 3.37 times more than Si.