Bunuel
A store calls the original price of an item the X-level price. The store reduces the X-level price of an item by 30%, resulting in what the store calls the Y-level price of the item. The store then reduces the Y-level price of the item by 20%, resulting in what the store calls the Z-level price of the item. The Z-level price of the item is less than $49. Which of the following statements must be true?
I. The X-level price of the item is less than $86.00.
II. When the Z-level price of the item is subtracted from the Y-level price of the item, the result is less than $16.00.
III. The Y-level price of the item is a percent greater than the Z-level price of the item, where \(0 < a < 30\).
A. I only
B. III only
C. I and II only
D. II and III only
E. I, II and III
Solution: - let the X level price be \(p\)
- So, Y level price \(=0.7p\)
- And Z level price \(=0.8\times 0.7p=0.56p\)
- According to the question, \(0.56p<49\) or \(p<87.5\)
I. The X-level price of the item is less than $86.00
- We know \(p<87.5\) so the value of p can be 87
- Thus this must not be true
II. When the Z-level price of the item is subtracted from the Y-level price of the item, the result is less than $16.00
- \(0.7p-0.56p<16\)
\(⇒0.14p<16\)
\(⇒p<114.xx\) - We know \(p<87.5\)
- Thus this must be true
III. The Y-level price of the item is a percent greater than the Z-level price of the item, where \(0 < a < 30\)
- \(\frac{0.7p-0.56p}{0.7p}\times 100=a\)
\(⇒\frac{0.14}{0.7}\times 100\)
\(⇒20\%\) which is in between 0 and 30 - Thus this must be true
Hence the right answer is
Option D