Problem 17 · 2009 Math Kangaroo
Hard
Algebra & Patterns
sum-constraintwork-backward
A white and a black pig weigh together 320 kg. The black pig weighs 32 kg more than the white one. How much does the white pig weigh?
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Answer: B — 144 kg
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Hint 1 of 2
If the pigs weighed the same, each would be 160 kg.
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Hint 2 of 2
The black pig is 32 kg heavier, so split that extra evenly.
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Approach: split the difference
- Together the pigs weigh 320 kg, so equal pigs would be 160 kg each.
- The black pig is 32 kg more than the white pig.
- Give half of 32 (which is 16) to the black and take 16 from the white: white = 160 − 16 = 144 kg.
- The white pig weighs 144 kg.
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