Bunuel
The original cost of a mobile was $799. Mr. Thomas increased the price by p% and gave a discount of d% on the increased price. Was the new cost less than the original cost?
(1) p = d
(2) 100p - 100d < pd
Mr. Thomas increased the price by p% and gave a discount of d% on the increased price
--> New cost = \(799*(1 + \frac{p}{100})*(1 - \frac{d}{100})\)
--> New cost = \(799*(1 + \frac{p}{100} - \frac{d}{100} - \frac{pd}{10000})\)
(1) p = d
--> New cost = \(799*(1 + \frac{p}{100} - \frac{p}{100} - \frac{p^2}{10000})\)
--> New cost = \(799*(1 - \frac{p^2}{10000})\)
For any value of p, \((1 - \frac{p^2}{10000})\) is always less than 1
--> New cost is ALWAYS less than original cost -->
Sufficient(2) 100p - 100d < pd
--> New cost = \(799*(1 + \frac{p}{100} - \frac{d}{100} - \frac{pd}{10000})\)
--> New cost = \(799*(1 + \frac{(100p - 100d - pd)}{10000})\)
Since \(100p - 100d < pd\)
--> \(100p - 100d - pd < 0\)
New cost = 799*(fraction less than 1), which is less than original cost -->
SufficientIMO Option D
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