# Calculation puzzle 008

What is x?

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| 22 |
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| 34 | 23 |
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| 57 |
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| 43 |
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| 78 | 29 |
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| 16 |
-----

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| 52 |
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| 94 | 28 |
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| 35 |
-----

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| 62 |
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| 71 | x  |
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| 23 |
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There is a connection between the numbers. The same connection applies to all four parts and then we can find x.

I tried to do it, but couldn't solve. In the first one, 22+23+57=112 and 34*3=102, so 112-10=102. This method doesn't apply to the others. Added altogether to no avail. Multiplied digits, still no answer.

The answer shown on the booklet is 21.

Source: The question is asked in YTUYOS 2017 booklet A, question no: 57. These are the questions asked in university entrance exam for international students in Turkey. These types of questions should not take more than 2 minutes to solve and generally they do have only one answer. In case they have more than one then the question is cancelled.

21

This is because, simply:

The number on the right is the sum of all of the digits in the three left-hand boxes:

(2 + 2) + (3 + 4) + (5 + 7) = 23
(4 + 3) + (7 + 8) + (1 + 6) = 29
(5 + 2) + (9 + 4) + (3 + 5) = 28

and thus:

(6 + 2) + (7 + 1) + (2 + 3) = 21

• Thank you. I couldn't think that way when I was trying to solve it. Good approach, I appreciate it. – garakchy Jul 15 '20 at 22:10