The difference between a two-digit number and the number obtained by interchanging the positions of its digits is 36. What is the difference between the two digits of that number?
Answer: B
Let the ten's digit be \(x\) and unit's digit be \(y\)
Then,
\((10x + y) - (10y + x) = 36\\
\Rightarrow 9(x - y) = 36\\
\Rightarrow x - y = 4\)