there are p pens in a pack. 2 of them do not work. write an expression for the number of working pens in a pack

Line the mark up so you will find your answer

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.

The density of the cube is 40