Two natural numbers whose sum is 72 cannot be in the ratio:
Correct answer: D. 3:4
- A. 1:2
- B. 3:5
- C. 1:3
- D. 3:4
Explanation
For a ratio a:b and total 72, the sum of ratio parts must divide 72. Ratios 1:2, 3:5 and 1:3 give integer pairs, but 3:4 has 7 parts and 72 ÷ 7 is not a natural number, so it cannot form the required pair. The likely mistake is option c, 1:3, which gives the valid pair 18 and 54.
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About Ratio and Proportion
Ratios compare quantities in the same units, while proportions state that two ratios are equal. Problems cover simplification, division in a given ratio, direct and inverse variation, scale, and missing terms, with attention to the difference between a ratio and a fraction representing part of a whole.
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