CSATNumber System & SeriesDigits Arithmetic2024

Let X be a two-digit number and Y be another two-digit number formed by interchanging the digits of X. If (X + Y) is the greatest two-digit number, then what is the number of possible values of X?

A

2

B

4

C

6

D

8

Correct Answer: Option D

Explanation

1. **Formulate the Equation**: Let the number X be $10a + b$. Its reverse Y is $10b + a$. The problem states their sum is the 'greatest two-digit number',

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