If the sum of the two-digit numbers AB and CD is the three-digit number 1CE, where the letters A, B, C, D, E denote distinct digits, then what is the value of A?

Correct Option

The problem states that the sum of two-digit numbers AB and CD results in the three-digit number 1CE, where A, B, C, D, E denote distinct digits.

We can express these numbers using their place values:

• AB = 10A + B
• CD = 10C + D
• 1CE = 100 + 10C + E

The given equation is (10A + B) + (10C + D) = 100 + 10C + E.

Let's analyze the sum based on place values:

Case 1: No carry-over from the units place to the tens place (B + D = E)

If B + D = E, then the sum of the tens digits (A + C) must generate a carry-over of 1 to the hundreds place, and the tens digit of the sum must be C. This implies that A + C = 10 + C.

$\therefore$ A + C = 10 + C

$\Rightarrow$ A = 10

This result is not possible because A must be a single digit (0-9). Furthermore, as the tens digit of a two-digit number AB, A cannot be 0. Therefore, this case is invalid.

Case 2: A carry-over of 1 from the units place to the tens place (B + D = 10 + E)

If B + D = 10 + E, then a carry-over of 1 is added to the sum of the tens digits (A + C).

For the sum to be 1CE, the sum of the tens digits (A + C + 1, including the carry-over) must result in 10 + C (where 'C' is the tens digit of 1CE and '1' is the hundreds digit).

$\therefore$ A + C + 1 = 10 + C

$\Rightarrow$ A + 1 = 10

$\Rightarrow$ A = 9

This value of A = 9 is a valid single digit. Given that A, B, C, D, E must be distinct, a valid set of digits can be found (e.g., A=9, C=1, B=2, D=8, E=0, where 92 + 18 = 110, which matches the 1CE format). Hence, A = 9 is the uniquely determined value.

Incorrect Options

Options 2 (8), 3 (7), and 4 (Cannot be determined due to insufficient data) are incorrect.

• The logical deduction, based on the principles of place value arithmetic and the given conditions, uniquely determines the value of A as 9.
• Any other value for A, such as 8 or 7, would contradict the derived equation A + 1 = 10.
• Since a unique and valid value for A can be determined through this systematic approach, the assertion that the value "Cannot be determined due to insufficient data" is incorrect.