We know that the digit at the units place is double the digit in the tens place.
So let’s consider the tens place as y
The digit at the unit place is 2y
So the equation is (10y + 2y) = 12y…………….. Equation (1)
From the question, the number exceeds the sum of its digits by 18
∴from the above condition, (y + 2y) + 18……….. Equation (2)
Combining equation 1 and 2 we get,
(y + 2y) + 18 = (10y + 2y)
3y + 18 =12y
18 = 12y -3y
18 = 9y
∴ y = 2
Hence, the digit tens place is 2
The digit unit place is 2y = 2(2) = 4
Substituting the value of y in equation 1 we get,
12y
12(2) = 24
∴ The required number is 24.