Problem 11 · 2015 Math Kangaroo
Medium
Arithmetic & Operations
total-then-divide
Julia has 9 sweets and Katharina has 17 sweets. How many sweets does Katharina have to give to Julia so that they both have the same amount of sweets?
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Answer: C — 4
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Hint 1 of 3
Katharina has more sweets than Julia, so she needs to give some away to make them even.
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Hint 2 of 3
Find the gap between their piles, then think about sharing that gap fairly.
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Hint 3 of 3
Whatever Katharina gives, Julia gains, so each sweet given closes the gap by two.
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Approach: share the difference equally
- Line up the piles: Julia has 9 and Katharina has 17, so Katharina has 8 more.
- Each time Katharina gives one sweet, she loses one and Julia gains one, so the gap shrinks by 2.
- To close a gap of 8 the gap must shrink 4 times, so Katharina gives 4 sweets and both end with 13, choice C.
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