Step-by-step explanation:
If the tens digit of the number is X and the ones digit is Y then the number is equal to 10*X + Y
If you reverse the digits then the number is equal to 10*Y + X
If reversing the digits decreases the number by 36 then
10*Y + X = 10*X + Y - 36
The sum of the digits is 4 so X + Y = 4 ==> X = 4 - Y
Substitute this value of X into the 1st equation
10*Y + (4 - Y) = 10*(4 - Y) + Y - 36
9*Y + 4 = 40 - 9*Y - 36
18*Y = 0
Y = 0
I hope it helps you
So X = 4 - 0 = 4 and the number is 40
so, let's check 40 - 04 = 36
