To find the probability that a randomly selected medal is not a gold medal, we need to consider the total number of medals that are not gold and divide it by the total number of medals.

Total number of medals = 30 (gold) + 22 (silver) + 18 (bronze) = 70 medals

Number of medals that are not gold = 22 (silver) + 18 (bronze) = 40 medals

Now, the probability of selecting a medal that is not gold is:

\(\text{Probability} = \frac{\text{Number of medals that are not gold}}{\text{Total number of medals}} = \frac{40}{70} = \frac{4}{7}. \)