Problem 18 · 2020 Math Kangaroo
Medium
Fractions, Decimals & Percents
percent-multiplier
A store announced a 30% discount for a sale. However, one day before the promotion the store raised the prices of all its products by 20%. What was the real discount the store gave on the day of the sale?
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Answer: D — 16%
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Hint 1 of 2
Start from a price of 100; apply the 20% increase first, then the 30% discount.
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Hint 2 of 2
Compare the final price with the original 100 to read off the real discount.
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Approach: chain the two percentage multipliers
- Take the original price as 100. Raising by 20% gives 100 × 1.2 = 120.
- Then the 30% sale discount gives 120 × 0.7 = 84.
- The customer pays 84 instead of 100, a real discount of 16%.
- The answer is 16%, choice D.
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