Bunuel
The absolute difference between a two-digit number and the number formed by reversing the digits of that number is D. What is the number?
(1) D = 36
(2) The sum of the digits of the number is 12.
Reversing digits is a common number property topic. If we represent two digits with x and y, we can build two numbers with reversed digits: \(10x + y\) and \(x + 10y\). Their difference would be \(9x - 9y\) or \(9y - 9x\), either way the difference is divisible by 9 and we can represent the difference with \(9*|x -y|\).
Statement 1:Plugging in what we had above, we can find |x - y| = 4, hence the digits have an absolute difference of 4. There are too many options so insufficient.
Statement 2:Even if we found a single combination of digits, we still have two different numbers by reversing the digits. Insufficient.
Combined:We have the same problem in both statements, we can find a specific combination of digits (digits 8 and 4) but we don't know if we want the smaller number (48) or larger number (84). Insufficient.
Ans: E