Q and R are two-digit positive integers that have the same digits but in reverse order. If the positive difference between Q and R is less than 60, what is the greatest possible value of Q minus R?	Choose the correct choice.
A) 52  B) 54  C) 55  D) 56  E) 58

Rationale: "a two - digit integer ` ` ab ' ' can be expressed algebraically as 10 a + b . q - r = ( 10 a + b ) - ( 10 b + a ) = 9 ( a - b ) < 60 . the greatest multiple of 9 which is less than 60 is 54 . the answer is b ."
Answer: B