The difference between a number and its two-fifths is 510. What is 10% of that number?
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Answer: B. 85
Explanation
Subtracting two-fifths from a whole number leaves three-fifths of the original number. Setting three-fifths of the number equal to 510 yields an original number of 850. Calculating ten percent of 850 results in the final answer of 85. A number minus two-fifths of itself is expressed algebraically as x minus 2x over 5. Solving 3x over 5 equals 510 gives x equal to 510 times 5 divided by 3. Ten percent of any number is calculated by dividing that number by ten.
Fractional reduction problems frequently appear in basic arithmetic and aptitude tests. Business calculations often require finding percentage portions of derived totals. Algebraic word translation builds foundational skills for advanced mathematical modeling. Choosing 12.75 is an incorrect fractional calculation unrelated to ten percent of the number. Choosing 204 represents twenty-four percent instead of ten percent of the number. Choosing none of these is incorrect because 85 is a valid calculated option.
- Subject
- Mathematics
- Category
- Mathematics
- Topic
- —
- Difficulty
- medium
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