To calculate the experimental probability of landing on a 3 when rolling a six-sided number cube, 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 event is landing on a 3, which occurs 10 times, and the total number of trials (rolls) is 30.
Using the values:
\[ \text{Experimental Probability of landing on a 3} = \frac{10}{30} \]
To simplify this fraction, divide both the numerator and the denominator by their greatest common divisor, which is 10:
\[ \frac{10 \div 10}{30 \div 10} = \frac{1}{3} \]
Thus, the experimental probability of landing on a 3 is:
\[ \frac{1}{3} \]