Difficulty: Easy
Correct Answer: 78%
Explanation:
Introduction / Context:This percentage-and-ratio question asks for the proportion of students who are not scholarship holders, given the gender ratio and the scholarship percentages for each group. The key is to use a convenient base matching the ratio, compute weighted adults (scholarship holders), then subtract from 100%.
Given Data / Assumptions:
Concept / Approach:Work with a ratio base (e.g., 5k total students so that boys = 3k and girls = 2k). Compute scholarship holders in each group, sum them, convert to an overall percentage, and finally find the complement for non-scholarship students.
Step-by-Step Solution:
Assume total = 5k ⇒ boys = 3k, girls = 2k.Scholarship boys = 20% of 3k = 0.6k.Scholarship girls = 25% of 2k = 0.5k.Total scholarships = 0.6k + 0.5k = 1.1k.Scholarship % of all students = 1.1k / 5k * 100 = 22%.Non-scholarship % = 100% − 22% = 78%.Verification / Alternative check:Pick actual numbers (boys 300, girls 200). Scholarship holders = 20% of 300 (60) + 25% of 200 (50) = 110 of 500 total ⇒ 22% scholarships → 78% not on scholarship.
Why Other Options Are Wrong:75% and 60% come from unweighted or incorrect averaging; 55% is far too low; 72% is a nearby distractor but not the computed complement of 22%.
Common Pitfalls:Simply averaging 20% and 25% without weighting by the 3 : 2 ratio gives the wrong total scholarship rate.
Final Answer:78%
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