Problem 7 · 2019 Math Kangaroo
Easy
Logic & Word Problems
work-backward
There are two kinds of camels: bactrian camels that have 2 humps, and dromedaries that have 1 hump. Exactly 10 camels live in a certain zoo. Together they have 14 humps. How many bactrian camels are there in this zoo?
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Answer: D — 4
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Hint 1 of 2
If all 10 camels had just 1 hump, how many humps would that be?
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Hint 2 of 2
Every bactrian camel adds one extra hump beyond that; the extra humps tell you the count.
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Approach: start from all one-hump and add the extra humps
- If all 10 camels had 1 hump each, that would be 10 humps.
- There are 14 humps, so there are 4 extra humps.
- Each bactrian camel has one extra hump, so there are 4 bactrian camels.
- The answer is D.
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