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Re: Between the first day of May and last day in June, the price
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17 Apr 2017, 09:45
Explanation
Since the problem doesn’t give you prices, Plug In; since the question involves percents, use 100. If the starting price for Melange was $100, then, after the 20% decrease, the price was $80; increase that by 50%, or \(\frac{1}{2}\), and the ending price was $120. Since the ending prices for
Melange and Blue were the same, the ending price for Blue was also $120.
Now, work backwards. Declining by 50% is the same as being cut in half; if Blue was $120 after being cut in half, it must have been $240 before the decrease. Since that $240 was the result of a 20% increase, translate the question “240 is 120% of what” to get the equation \(240 = \frac{120}{100} \times x\); solve for x to get the starting price for Blue, $200. Finally, now that you have both starting prices, translate the question into \(20 = \frac{x}{100} \times 100\), and solve for x to get your answer, 200.
Hence option E is correct!