The ratio of the number of adults to the number of students at the prom has to be 1: 10. last year there were 477 more students than adults at the prom. if the school is expecting the same attendance this year, how many adults have to attend the prom?

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.