Topics › Percentage › Q111
At a shop in Toa Payoh, the price of a pair of sports shoes was first increased by 20%. Later, during a sale, the new price was decreased by 25%. The sale price was $72. What was the original price of the shoes?
Try it yourself · watch the animation →Take the original price as 100% and draw 10 units. How many units after the 20% increase? The 25% decrease is 25% of the new price.
Answer: Original price 80 $
Method: Use a 100% bar model for the original amount. Extend the bar for the percentage increase, then reduce the required percentage from the increased bar. Match the remaining units to the final amount given.
50 $ — The original price is 100%. After a 20% increase, it becomes 120%. After a 10% decrease, 90% × 120% = 108% of the original price remains. 108% corresponds to $54, so 1% corresponds to $0.50 and 100% corresponds to $50.
200 张 — The original number of cards is 100%. After a 30% increase, it becomes 130%. After giving away 20%, 80% × 130% = 104% of the original number remains. 104% corresponds to 208 cards, so 1% corresponds to 2 cards and 100% corresponds to 200 cards.
800 $ — The original price is 100%. After a 25% increase, it becomes 125%. After a 24% decrease, 76% × 125% = 95% of the original price remains. 95% corresponds to $760, so 1% corresponds to $8 and 100% corresponds to $800.
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