During the Memorial High School highway clean-up project, Ms. Palkowski cleaned 0.125 of a mile for the teachers' team and
then 0.4 of a mile for the science club. How much did she clean
altogether?

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.