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Multiplication with a twist

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Multiplication with a twist

by mj78ind » Tue Aug 10, 2010 9:19 pm
Let AB be a two digit number, AB*BA = CBCA, and A(A+C) = B, what is the number?

1. 43
2. 26
3. 41
4. 61
5. 86

[spoiler]Answer 2. 26
I did this question by using each choice and multiplying by its reverse and observing results. This got me the answer but seems tough to crack in 2.5 mins, does anyone have a faster approach?[/spoiler]
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by Rahul@gurome » Tue Aug 10, 2010 11:29 pm
Solution:
Since A(A+C) = B, A should divide B.
Only 26 satisfies this criteria.
Correct answer is hence 2.
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Master | Next Rank: 500 Posts
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by mj78ind » Tue Aug 10, 2010 11:37 pm
Rahul@gurome wrote:Solution:
Since A(A+C) = B, A should divide B.
Only 26 satisfies this criteria.
Correct answer is hence 2.
@Rahul, great insight there, thanks!
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