2. What is the perimeter of triangle ABC above？

　　（1） The ratio of DE to BF is 1： 3.

　　（2） D and E are midpoints of sides AB and CB， respectively.

　　Since we do not even know whether BF is an altitude， nothing can be determin

　　ed from （1）。 More importantly， there is no information telling us the absolu

　　te size of the triangle.

　　As to （2）， although from geometry we know that DE = AC/2， this relationship

　　holds for any size triangle. Hence， （2） is also insufficient.

　　Together， （1） and （2） are also insufficient since we still don't have inform

　　ation about the size of the triangle， so we can't determine the perimeter. T

　　he answer is E.

　　3. A dress was initially listed at a price that would have given the store a

　　profit of 20 percent of the wholesale cost. What was the wholesale cost of

　　the dress？

　　（1） After reducing the asking price by 10 percent， the dress sold for a net

　　profit of 10 dollars.

　　（2） The dress sold for 50 dollars.

　　Consider just the question setup. Since the store would have made a profit o

　　f 20 percent on the wholesale cost， the original price P of the dress was 12

　　0 percent of the cost： P = 1.2C. Now， translating （1）sintosan equation yield

　　s：

　　P - .1P = C + 10

　　Simplifying gives

　　……9P = C + 10

　　Solving for P yields

　　P = （C + 10）/.9

　　Plugging this expression for PsintosP = 1.2C gives

　　（C + 10）/.9 = 1.2C

　　Since we now have only one equation involving the cost， we can determine the

　　cost by solving for C. Hence， the answer is A or D.

　　（2） is insufficient since it does not relate the selling price to any other

　　information. Note， the phrase “initially listed” implies that there was more

　　than one asking price. If it wasn't for that phrase， （2） would be sufficien

　　t. The answer is A.