A quantity with an initial value of 130 decays exponentially at a rate such that the quantity cuts in half every 9 weeks. What is the value of the quantity after 21 days, to the nearest hundredth?

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.