Question

Find the value of A in the addition.

$$\begin{array}{c}A\\ +A\\ +A\\ BA\end{array}$$

• A. 1
• B. 5
• C. 3
• D. 2

Answer 1

The correct option is B

5

This has two letters A and B whose values are to be found.

Study the addition in the ones column: the sum of three A's is a number whose ones digit is A.

Therefore, the sum of two A's must be a number whose ones digit is 0.

This happens only for A = 0 and A = 5.

If A = 0, then the sum is 0 + 0+ 0 = 0, which makes B = 0 too.

We do not want this (as it makes A = B, and then the tens digit of BA too becomes 0),
Also we can check these using algebric expression.
$3A=10\times B+A$
$\Rightarrow$ $2A=10\times B$
$\Rightarrow$$B=\frac{A}{5}$
The above solution satisfies this relation. So, A = 5.

Therefore, the puzzle is solved as shown below.

$$\begin{array}{c}5\\ +5\\ +5\\ 15\end{array}$$

That is, A= 5 and B= 1