If a two-digit positive integer has its digits reversed, the resulting integer differs from the original by 45. By how much do the two digits differ?
Select
A) 3	B) 4	C) 5	D) 6	E) 7
we are given that if the integer N has its digits reversed the resulting integer differs from the original by 45. First let’s express the reversed number in a similar fashion to the way in which we expressed the original integer.   10B + A = reversed integer   Since we know the resulting integer differs from the original by 45 we can say:   10B + A – (10A + B) = 45   10B + A – 10A – B = 45   9B – 9A = 45   B – A = 5   Since B is the tens digit and A is the units digit, we can say that the digits differ by 5.   The answer is 5.
<result>C</result>
If a two-digit positive integer has its digits reversed, the resulting integer differs from the original by 45. By how much do the two digits differ?