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The remainder when $'m+n'$ is divided by $12$ is $8$, and the remainder when $'m-n'$ is divided by $12$ is $6$. If $m>n$, then what is the remainder when $'mn'$ is divided by $6$?
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$m + n = 12k_1 + 8  ------------------(1)$

$m - n = 12k_2 + 6  --------------- (2)$

Observe here $k_1$ will be greater than or equal to $k_2$

Adding $(1)\ and\ (2)$

$2m = 12(k_1+k_2+1) + 2$

let $k_1+k_2+1 = k_3$

  $m = 6(k_3) + 1$

Similarly by subtracting $(2)$ from $(1),$

$n = 6(k_4) + 1$

Now $mn = 36(k_3)(k_4) + 6(k_3) + 6(k_4) + 1$

       $= 6(k_5) + 1$

Clearly now $mn$ when divided by $6$, will leave remainder $\textbf{1}$
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m+n = 8

m-n = 6

So, by evaluating , we will get 2m=14

so, m=7, n=1

mn/6 = 7*1/6 = 1 is remainder

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