data sufficiency

[sanyu4]

Question from the Fractions Decimals and percents - 4th edition, guide 2: Page 21 Number 11:

The number A is a two-digit positive integer; the number b is the two digit positive integer formed by reversing the digits of A. If Q = 10B-A, what is the value of Q?

I do not understand the explanation in the book, can you give me an alternate explanation?

Thank you

[jnelson0612]

sanyu, will you please add the two statements? This is a data sufficiency question and it will help the students who see this problem to have all the information. Once you do this someone will help you, thanks!