Probability of an event =(Number of favorable outcomes)/(Total number of outcomes)
Here, the number of favorable outcomes is the number of times 3 comes up.
The number of times 3 comes up = 67
Total number of outcomes is the number of times the cube is rolled.
Total number of times the cube is rolled = 450
Therefore, Probability of getting a 3 =67/450
Since 67 is a prime number, 67/450 is the final answer in simplest form.