Given that the mean of 10 values is 86.2, we have:

\(\frac{\Sigma x}{10} = 86.2\)

Therefore, \(\Sigma x = 86.2 \times 10 = 862\).

For part (ii), we know \(\Sigma(x-a) = 362\).

Expanding this, we have:

\(\Sigma x - 10a = 362\)

Substituting \(\Sigma x = 862\) from part (i):

\(862 - 10a = 362\)

Solving for \(a\):

\(10a = 862 - 362\)

\(10a = 500\)

\(a = 50\)