A number between 10 and 60 has digits which differ by 5 and the digits also add to 5

Question

I can't work out this question

Answer 1

n and m are the 2 digits.

 

n - m = 5

n + m = 5

 

Solve for n and m.  Add the 2 equations and get

 

2n = 10

n = 5

 

Then 

 

m = 5 - n = 5 - 5 = 0

 

The number must be 50.

Answer 2

Let the number be ab, a>1.b>=0

a-b=5

a+b=5

a=5

b=0

The number is 50.