Solution:
Note that you can repeat numbers.
3 numbers between 1 to 30 including 1 and 30.
that means (30-1)+1=30 numbers.
3 slots that can be repeated, so there is the following number of combinations:
[tex]30^{3\text{ }}=\text{ }27000[/tex]in 100 attempts, that is a 100/27000=1/270 chance or about 0.37% chance. We can conclude that the correct answer is:
[tex]\frac{100}{27000}\text{ = }\frac{1}{270}\text{ }[/tex]