Problem 3 · 2013 Math Kangaroo
Easy
Ratios, Rates & Proportions
ratioproportion
In sea water the ratio of salt to fresh water is 7 : 193. How many kilograms of salt are there in 1000 kg of sea water?
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Answer: A — 35
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Hint 1 of 2
Salt to fresh is 7 : 193, so think in equal-sized parts that make up the whole.
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Hint 2 of 2
Add the parts to see how big one part is in kilograms.
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Approach: parts of a ratio
- The ratio 7 : 193 means 7 + 193 = 200 equal parts make the sea water.
- 1000 kg ÷ 200 parts = 5 kg per part.
- Salt is 7 parts: 7 × 5 = 35 kg.
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