The answer is: 63 . ______________________________________________________ Explanation: ______________________________________________________ First, let's list all the 2-digit multiples of "9": ______________________________________________________ 18, 27, 36, 45, 54, 63, 72, 81, 90, 99. ______________________________________________________ From this list, the only answer that has a ratio in which its "units digits to its tens digits" is "1:2" is: "63" . "3:6" = "1:2" .
So the answer is: 63 . _______________________________________________________
