Answer:
39
Explanation:
let the 2 digit number be ab = 10a + b ( considering place value )
The reversed 2 digit number is ba = 10b + a
The sum of the 2 digit number is
a + b = 12 ( subtract b from both sides )
a = 12 - b → (1)
Expressing as an equation
ba = ab + 54 , that is
10b + a = 10a + b + 54
Substitute a = 12 - b into the equation
10b + 12 - b = 10(12 - b) + b + 54 , simplify both sides
9b + 12 = 120 - 10b + b + 54
9b + 12 = - 9b + 174 ( add 9b to both sides )
18b + 12 = 174 ( subtract 12 from both sides )
18b = 162 ( divide both sides by 18 )
b = 9
Substitute b = 9 into (1)
a = 12 - 9 = 3
Thus
the original 2 digit number = ab = 39
The reversed 2 digit number = ba = 93
which is 54 more than the original number