Answer:
2/3, or 66.7%
Step-by-step explanation:
There are 2 options for the first digit (3 or 4).
After the first digit is selected, it cannot be repeated, so there are 2 options left for the second digit.
After the first two digits are selected, there is only 1 option for the third digit.
So there are 4 permutations greater than 300.
The total number of permutations is 3! = 6.
So the probability is 4/6 = 2/3.