When a number is first increased by 10 % and then reduced by 10 % the number:__________?
Correct answer: B. decreased by 1 %
- A. does not change
- B. decreased by 1 %
- C. increased by 1 %
- D. None of these
Explanation
Take the original number as 100 units. After a 10% increase it becomes 110 units, and reducing this by 10% gives 110 × 0.90 = 99 units, which is 1% less than the original 100 units. A student may choose a, does not change, by assuming that a 10% increase and a 10% decrease cancel despite applying to different bases.
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About Percentages
Percentages express a quantity as parts per hundred and support calculations involving increases, decreases, discounts, commissions, taxes, and successive changes. Questions require distinguishing percentage change from percentage points and identifying the original value when a final value and its percentage change are given.
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