Let the probability of landing on the blue side be \(p\).

Then the probability of landing on the red side is \(4p\), and the probability of landing on the green side is \(3p\).

Since the total probability must equal 1, we have:

\(4p + p + 3p = 1\)

\(8p = 1\)

\(p = \frac{1}{8}\)

Thus, the probability of landing on the blue side is \(\frac{1}{8}\).

For part (ii), the probabilities are:

\(P(R) = \frac{1}{2}\), \(P(B) = \frac{1}{8}\), \(P(G) = \frac{3}{8}\).

The probability that the spinner lands on a different coloured side each time is:

\(P(\text{all different}) = \frac{1}{2} \times \frac{1}{8} \times \frac{3}{8} \times 3!\)

\(= \frac{9}{64}\)

Therefore, the probability is \(\frac{9}{64}\) or approximately 0.141.