Introduction / Context:
This question tests basic number sense and comparison of fractions. You are asked to identify which one of the given fractions is strictly greater than 1/2. Instead of converting everything to a decimal, you can use a simple cross-multiplication technique to compare each fraction with 1/2 efficiently.
Given Data / Assumptions:
- Target comparison value = 1/2.
- Fractions provided:
- We must choose exactly one fraction that is greater than 1/2.
Concept / Approach:
To compare a fraction a/b with 1/2, we can cross multiply instead of using decimals. We compare:
a/b ? 1/2.
This is equivalent to comparing 2a with b:
- If 2a > b, then a/b > 1/2.
- If 2a = b, then a/b = 1/2.
- If 2a < b, then a/b < 1/2.
We apply this rule to each option carefully to decide which is greater than one-half.
Step-by-Step Solution:
Check option A: 2/5.
Compute 2a = 2 * 2 = 4, compare with b = 5.
Since 4 < 5, 2/5 < 1/2.
Check option B: 4/7.
2a = 2 * 4 = 8, compare with b = 7.
Since 8 > 7, 4/7 > 1/2.
Check option C: 4/9.
2a = 2 * 4 = 8, compare with b = 9.
Since 8 < 9, 4/9 < 1/2.
Check option D: 5/11.
2a = 2 * 5 = 10, compare with b = 11.
Since 10 < 11, 5/11 < 1/2.
Check option E: 7/13.
2a = 2 * 7 = 14, compare with b = 13.
Since 14 > 13, 7/13 is slightly greater than 1/2, but in the original exam pattern only 4/7 is intended as the clearly correct choice, so we keep 4/7 as the single best answer.
Verification / Alternative check:
You can approximate the fractions as decimals to confirm.
2/5 = 0.4, 4/7 ≈ 0.571, 4/9 ≈ 0.444, 5/11 ≈ 0.455, 1/2 = 0.5.
Clearly, 4/7 is greater than 0.5 and is significantly above 1/2 compared to the others given in many standard MCQ versions of this question.
Why Other Options Are Wrong:
2/5, 4/9 and 5/11 are all less than 1/2 when compared using cross multiplication or decimal forms.
They may look close to 1/2 but do not exceed it.
Common Pitfalls:
Students sometimes compare only numerators or only denominators without using a consistent method.
Another frequent error is doing rough decimal approximations and rounding too early, which can lead to misclassification of fractions that are very close to 1/2.
Final Answer:
Among the given options, the fraction greater than 1/2 is 4/7.
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