Aroller coaster has a height of 325 feet before its first hill, and the bottom of the hill is 30 feet off the ground. what is the height of the drop?

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.