Difficulty: Medium
Correct Answer: 12
Explanation:
Introduction / Context: The number of sweets per child depends on the number of children, and the problem links them: each child’s share is 20% of the headcount. This yields a quadratic relation in the number of children.
Given Data / Assumptions:
Concept / Approach: Total sweets = (children) * (sweets per child) = n * (0.20n) = 0.20n^2. Set that equal to 720 and solve for n. Then compute each child’s share using 0.20n.
Step-by-Step Solution:
0.20n^2 = 720 ⇒ n^2 = 720 / 0.20 = 3600 ⇒ n = 60 (positive root).Sweets per child = 0.20 * n = 0.20 * 60 = 12.Verification / Alternative check: Total sweets check: 60 children * 12 sweets = 720, consistent.
Why Other Options Are Wrong: 14, 11, 15, 10 do not satisfy the quadratic relationship when multiplied by the corresponding child count.
Common Pitfalls: Treating 20% of children as 20% of sweets, or assuming a linear relation. The share per child depends on n, producing n^2.
Final Answer: 12
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