the difference between a 2-digit number and the number obtained by interchanging its digit is 63.what is the difference between the digits of the number.
Let the units digit be b and tens digit be a.
Then the number is
10a+b
Now interchanging the digits the number becomes
10b+a
Now difference between the numbers are
10a+b-(10b+a) = 10a+b-10b-a = 9a-9b
Now factorising we get
9(a-b) = 63
a-b = 7
So the answer is 7.