Question 1197421
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|| _ || 7 || _ || _ || _ || 10 || _ ||
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Let x be the number in the first box.<br>
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|| x || 7 || _ || _ || _ || 10 || _ ||
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The sum of the numbers in boxes 1 to 3 is 25, so the number in box 3 is 18-x.<br>
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|| x || 7 || 18-x || _ || _ || 10 || _ ||
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The sum of the numbers in boxes 2 to 4 is 25, so the number in box 4 is x.<br>
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|| x || 7 || 18-x || x || _ || 10 || _ ||
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The sum of the numbers in boxes 3 to 5 is 25, so the number in box 5 is 7.<br>
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|| x || 7 || 18-x || x || 7 || 10 || _ ||
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The sum of the numbers in boxes 4 to 6 is 25, so the number in box 4 is 8.<br>
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|| x || 7 || 18-x || 8 || 7 || 10 || _ ||
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ANSWER: 8<br>