Question

Find the values of A and B.
$\begin{array}{c}12A\\ +6AB\\ A09\end{array}$

• A. A = 8, B = 1
• B. A = 1, B = 8
• C. A = 9, B = 3
• D. A = 3, B = 9

Answer 1

The correct option is A A = 8, B = 1

In units place, we have ones digit of (A + B) = 9
Now, we know that A and B are single digits and thus their sum cannot be greater than 18.
$\Rightarrow$ A + B = 9
In the tens place, ones digit of (2 + A) = 0
$\Rightarrow$ A + 2 is a two digit number with 0 in its ones place.
$\Rightarrow$ A + 2 = 10
$\Rightarrow$ A = 8

A + B = 9
$\Rightarrow$ B = 1