Tham khảo tài liệu 'grubers complete sat guide 2009 phần 2', ngoại ngữ, ngữ pháp tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | STRATEGY SECTION 89 Tt a specific number. Let b 1. Then a 4b 4. So the average 1 4 _ 5 2 2 5 Look at choices where b 1. The only choice that gives is Choice C. EXAMPLE 7 EXAMPLE 5 The sum of three consecutive even integers is P. Find the sum of the next three consecutive odd integers that follow the greatest of the three even integers. A P 9 B P 15 C P 12 d P 20 E None of these. Choice B is correct. Try specifrc numbers. Let the three consecutive even integers be 2 4 6. So 2 4 6 P 12. The next three consecutive odd integers that follow 6 are 7 9 11 So the sum of 7 9 11 27. Now where P 12 look for a choice that gives you 27 A P 9 12 9 21 NO B P 15 12 15 27 YES EXAMPLE 6 If 3 a which of the following is not true A 3 - 3 a - 3 B 3 3 a 3 C 3 3 a 3 D 3 - 3 3 - a E f f Choice D is correct. Tryspecmc numbers. Work backward from Choice E if you wish. Let a 1. Choice E 3 a 1 TRUE STATEMENT Choice D 3 - 3 3 - a 3 - l or 0 2 FALSE STATEMENT In the figure of intersecting lines above which of the following is equal to 180 - a A a d B a 2d C c b D b 2a E c d Choice A is correct. I r. .- . i . Let a 20 Then 2a 40 Be careful now all of the other angles are now determined so don t choose any more. Because vertical angles are equal 2a b so b 40 I. Now c b 180 so c 40 180 and c 140 . Thus d 140 vertical angles are equal . Now look at the question 180 - a 180 - 20 160 Which is the correct choice A a d 20 140 160 that s the one 90 STRATEGY SECTION When Each Choice Must Be Tested Start with Choice E and Work Backward If you must check each choice for the correct answer start with Choice E and work backward. The reason for this is that the test maker of a question in which each choice must be tested often puts the correct answer as Choice D or E. In this way the careless student must check all or most of the choices before finding the correct one. So if you re trying all the choices start with the last choice then the next to last choice etc. EXAMPLE 1 If p is a .
