Percentage change
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Question 3
Ilana wants to buy a particular pair of jeans. Denim sells them for $88 excluding GST and Longpants sells them for $99 including GST. Assume GST is 10% of the cost of the jeans.
| a |  |
From which store should she buy the jeans? |
| b | What was the price of the Longpant's jeans before GST was added? |
Solution
| a |  |
10% of $88 = $8.80  (Divide by 10.) |
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| The cost of the jeans at Denim | = $88 + $8.80 | ||
| = $96.80 | |||
| So buy at Denim as the jeans are cheaper. | |||
| b | Let $x be the original price. | ||
| 1.1 × x = 99 (Divide by 1.1.) |
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| x = \(\dfrac{99}{100}\) = $90 | |||
| The original price was $90. | |||
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