To calculate the experimental probability of landing on a 3 when a six-sided number cube is rolled, you can use the formula:
\[ \text{Experimental Probability} = \frac{\text{Number of times the event occurs}}{\text{Total number of trials}} \]
In this case, the number of times the cube landed on 3 is 10, and the total number of rolls is 30.
So, the experimental probability of landing on a 3 is:
\[ \text{Experimental Probability} = \frac{10}{30} \]
To simplify this fraction:
\[ \frac{10}{30} = \frac{1}{3} \]
Thus, the experimental probability of landing on a 3 is:
\(\frac{1}{3}\)