tailieunhanh - Explanatory material: Data Sufficiency

The following disscusion of data sufficiency is intended to familiarize you with the most effecient and effective approaches to the kinds of problem common to data sufficiency. The problem on the sample questions you will encounted in this section of the GMAT remember that it is the problem- solving strategy is important, not the specific details of a particular question | Explanatory Material Data Sufficiency The following discussion of data sufficiency is intended to familiarize you with the most efficient and effective approaches to the kinds of problems common to data sufficiency The problems on the sample questions in this chapter are generally representative of the kinds of questions you will encounter in this section of the GMAT Remember J that it is the problem-solving strategy that is important not the specific details of a particular question 1 Ata certain picnic each of the guests was served either a single scoop or a double scoop of ice cream. How many of the guests were served a double scoop of ice cream 1. At the picnic 60 percent of the guests were served a double scoop of ice cream. 2 A total of 120 scoops of ice cream were served to all the guests at the picnic. I Statement 1 alone is not sufficient because the total number of guests is unknown. Thus. the answer must be B C or E Statement 2 alone is not sufficient since there is no information indicating how the 120 scoops were divided into single-scoop and double-scoop servings Thus the answer must be C or E From 1 the ratio of the number of guests who were served a single scoop to the number of guests who were served a double scoop can be deterrmned and can be used with 2 to determine the number of guests who were served a double scoop Thus the best answer is C It may be helpful to set up equations to determine whether there is sufficient information given in 1 and 2 for answering the question but it is not actually necessary to solve the equations 2. By what percent was the price of a certain candy bar increased 1 The price of the candy bar was increased by 5 cents. 2 The price of the candy bar after the increase was 45 cents. In 1 only the increase in pnce is given and both the original and final prices are unknown Thus the percent increase cannot be determined from 1 alone and the answer must be B C or E In 2 only the final price is given so the percent increase