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ds question

by ket_gmat » Sun Sep 07, 2008 6:52 am
□ 2
+
3 ∆
————
◙ ◊

In the correct addition shown above, all symbols represent different
nonzero digits.
What is th number represented by ◙ ◊?

1. □ = 2*∆
2. 10◙ + ◊ = 95


what is the answer and why?

:)
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Source: — Data Sufficiency |

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by Ian Stewart » Sun Sep 07, 2008 8:45 am
If you write a two-digit number x as AB, where A is the tens digit and B is the units digit, that means that x is equal to 10A + B. So 2) above is certainly sufficient; it tells you exactly that the number is equal to 95.

The first statement is insufficient only because there are two possible cases- we could have 22+ 31 = 53, or we could have 62 + 33 = 95. In both cases the sum is a two digit number, and each of the symbols represents a different digit.
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by gurudev » Sun Sep 07, 2008 8:54 am
but how can that satisfy :

□ +3 = □

is there something wrong in the question....
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by Ian Stewart » Sun Sep 07, 2008 9:57 am
gurudev wrote:but how can that satisfy :

□ +3 = □

is there something wrong in the question....
Perhaps the symbols aren't displaying properly in your browser? There are two different squares here, one white, one black. It' easier to see the problem with letters anyway; it should read:

A2
+ 3B
= CD

where A, B, C and D are distinct nonzero digits. What is CD?

1) A = 2B
2) CD is equal to 10*C + D
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