Answer:
The difference of the original two-digit number and the number with reversed digits is 18.
Step-by-step explanation:
Since it's a two digit number, let x represent the tens digit and let y represent the units digit.
Thus, the original two digit number is;
10x + y.
The reverse two digit number is;
10y + x.
We are told that five times the sum of the digits of the two-digit number is 13 less than the original number.
Thus;
5(x + y) = (10x + y) - 13
Multiplying out the bracket gives;
5x + 5y = 10x + y - 13
Rearranging gives;
10x - 5x + y - 5y = 13
5x - 4y = 13 - - - - (3)
Also,we are told that, four times the sum of its two digits is 21 less than the reversed two-digit number. Thus;
4(x + y) = (10y + x) - 21 - - - (4)
Simplifying gives;
4x + 4y = 10y + x - 21
>> 10y - 4y - 4x + x = 21
>> 6y - 3x = 21 - - - (4)
Solving eq(3) and (4) simultaneously gives;
x = 5 and y = 3
Thus,
Original number = 53
Reversed number = 35
Difference between original and reversed number = 53 - 35 = 18
and - 
