Question

Choose the correct answer from the alternatives given.
The difference between a two-digit number and the number obtained by interchanging the position of the digits is 45. What is the difference between the digits of that number?

• A. 4
• B. 5
• C. 6
• D. 7

Answer 1

Answer: (B)

5

Let the two digit number be $10x+y$ and its reverse be $10y+x$.
According to the question, $10x+y-(10y+x)=45$
$10x+y10y-x=45$ ⇒⇒ $9(x-y)=45$ ⇒$⇒
$x-y=5$
Hence, the difference between the digits is $5$.