The first side of a triangle is 9 m shorter than the second side. the third side is 3 times as long as the first side. the perimeter is 39 m. what is the length of the longest side?

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.