This is basically asking you to simplify the values and find the lowest ratio that compares their sizes. Starting with 27:36, you simplify. You could divide by 3, but 9 also works. Dividing both by 9 gives you 3:4, which is the most simplified answer.
only the first statement is true - it is the experimental probability. the rest is incorrect: the ratio is not the number of trials; the theoretical probability should be 0.5 (for unbiased coins); ratio never represents a number of occurences.
