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Logic Level 1

$\begin{array}{ccccc} & & & & A&B\\ + & & & & B &A\\ \hline & & & \phantom 0 & &\\ \hline \end{array}$

The resultant number must be a multiple of which of the following numbers?

9 10 11 12

3 solutions

Ralph James
May 4, 2016

Relevant wiki: Cryptogram

This is $(10A + B) + (10B+A) = 11B + 11A$ . Therefore, the resulting number must be a multiple of $\boxed{11}$ .

This solution and question is nice :)

Ashish Menon - 5 years, 1 month ago

Nashita Rahman
May 27, 2016

Sum of any 2-digit number and its reverse is always a multiple of 11.

For example, 21+12=33 which is divisible by 11

88+88=176 which is divisible by 11.

Hence, A B + B A is also divisible by 11 as BA is the reverse of AB.

Rex Holmes
May 9, 2016

AB or 12 + BA or 21 = 33 which is a multiple of 11