Difficulty: Easy
Correct Answer: 10:9
Explanation:
Introduction / Context:This is a direct ratio problem: compute counts of boys and girls and express them in simplest integer ratio form. Such questions check arithmetic accuracy and reduction to simplest terms.
Given Data / Assumptions:
Concept / Approach:Required ratio = Boys : Girls = 50 : 45. Divide both terms by their greatest common divisor (5) to simplify the ratio to lowest terms.
Step-by-Step Solution:Boys = 95 − 45 = 50.Raw ratio = 50 : 45.Divide by 5 ⇒ 10 : 9.
Verification / Alternative check:10 + 9 = 19 ratio parts; if each part represented 5 students, 19 * 5 = 95 total, consistent with the class size.
Why Other Options Are Wrong:Ratios 9:10 or 7:8 invert or misstate the counts; 9:11 is not equivalent to 50:45; 5:4 is 1.25, not matching 50/45 = 1.111…
Common Pitfalls:Accidentally giving Girls:Boys instead of Boys:Girls, or forgetting to reduce to simplest form.
Final Answer:10:9
Discussion & Comments