Problem 19 · 2021 Math Kangaroo
Hard
Logic & Word Problems
sum-constraint
The five cards shown (2, 3, 4, 5, 6) are placed into 2 boxes. The sums of the numbers in each box are the same. Which number must be in the box with the number 4?
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Answer: D — 6
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Hint 1 of 3
Add all five card numbers together first.
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Hint 2 of 3
Since the two boxes are equal, split that total in half to see what each box must hold.
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Hint 3 of 3
Now figure out which card the 4 needs next to it to reach that box total.
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Approach: find the equal totals and pair up
- All five cards add to 2 + 3 + 4 + 5 + 6 = 20, so each box must hold 10.
- Putting 2, 3, and 5 together makes 10, which leaves 4 and 6 for the other box.
- So the box with the 4 must also hold 6, option D.
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