Problem 13 · 2017 Math Kangaroo
Medium
Number Theory
divisibility
13 children registered for a competition. Then another 19 joined. Six equally big teams are needed for the competition. How many more children are needed, so that six equally big teams can be formed?
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Answer: D — 4
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Hint 1 of 2
First add the two groups of children together.
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Hint 2 of 2
Six equal teams means the total must split into 6 equal piles, so count up by sixes past your total.
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Approach: count up by sixes to the first number past the total
- Altogether there are 13 + 19 = 32 children.
- Six equal teams need a total that shares evenly into 6 piles, so count by sixes: 6, 12, 18, 24, 30, 36.
- The first one that is 32 or more is 36.
- So 36 - 32 = 4 more children are needed.
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