Answer:
41/293
Step-by-step explanation:
You have to be a little careful with the denominator. It must be the total of the columns which is the same total for the rows -- 586
The numerator is just the intersection of rats and Ravenclaw which is 82
So the answer is 82/586
The answer is also 41 / 293
In case you want the decimal it is .1399 rounded.