Someone me and show me how you got the answer super super in advance

18 liters of 100 is 18 percent. So the chemist would need 40 liters of acid to make a 40% acid solution.

18/100
=0.18
Convert it to a percent by moving the decimal point two places to the right.

So 40/100
=.40
Move the decimal point over two and add the percent sign.
40%

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.