The area of a rectangle is 600 square meters. The width is 30 meters. What is the length?

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.

Idk i am in 5th grade lol

It would take her 20 minutes.