A rational number is a number that can be written as a ratio that are whole numbers.
So we're trying to find out if 5 / 4 is in fact a ratio.
So 5/4 is equal to 1.25.
Since 1.25 is not a whole number, I don't think it is a rational number.
Sorry I accidentally clicked the answer button ';D
Correct me if I am wrong on this one.