gmat考试problemsolving复习资料(编辑修改稿)

gmat考试problemsolving复习资料(编辑修改稿)内容摘要：

【答案】 A 【思路 】 2c=3s,3s=4p 4p=18,p= 3s=18,s=6 代入 2c=3s,c=9 25. 3236!item!187。 058amp。 003282 26. 3282!item!187。 058amp。 003293 There are 10 children in a pany39。 s daycare center, and a pair of children is to be selected to play a game. At most, how many different pairs are possible? (A) 100 (B) 90 (C) 50 (D) 45 (E) 25 【答案】 D 【思路】 C(10,2)= 10!8!2!=45 27. 3330!item!187。 058amp。 003295 38, 69, 22, 73, 31, 47, 13, 82 Which of the following numbers is greater than threefourths of the numbers but less than onefourth of the numbers in the list above? (A) 56 (B) 68 (C) 69 (D) 71 (E) 73 【答案】 D 【思路】將上述的 sequence由小到大重新排列 13,22,31,38,47,69,73,82 假設題目要求的 number為 X,X大於數列的 34 ,小於 數列的 14 數列共有 8個數 , 34X8=6, 14X8=2 so, 69X73, 答案為 71(D) 28. 3377!item!187。 058amp。 003297 If xy = 1, what is the value of 2^[(x+y)^2] / 2^[(xy)^2] ? (A) 2 (B) 4 (C) 8 (D) 16 (E) 32 【答案】 D 【思路】根據 r rssx xx ,所以 2 2 2 2 2 2 22 2 2( 2 )( ) ( 2 ) 2 2 4()22 2222 x x y yx y x x y y x x y y x x y y x yxy            xy=1,故 the value= 42 =16 29. 3426!item!187。 058amp。 003323 The value of the expression above is closest to which of the following? (A) (B) (C) (D) 1 (E) 10 30. 3528!item!187。 058amp。 003455 A furniture dealer purchased a desk for $150 and then set the selling price equal to the purchase price plus a markup that was 40 percent of the selling price. If the dealer sold the desk at the selling price, what was the amount of the dealer39。 s gross profit from the purchase and the sale of the desk? (A) $40 (B) $60 (C) $80 (D) $90 (E) $100 【答案】 E 【思路】 selling price=the purchase price+ 40%selling price selling price =150+ selling price selling price=150 selling price=250, the gross profit=250150=100 31. 4014!item!187。 058amp。 003590 The circle shown has center O and radius 4. What is the area of the shaded region? (A) 3π (B) 4π (C) 6π (D) 8π (E) 12π 32. 4438!item!187。 058amp。 003962 At a certain university, the ratio of the number of teaching assistants to the number of students in any course must always be greater than 3:80. At this university, what is the maximum number of students possible in a course that has 5 teaching assistants? (A) 130 (B) 131 (C) 132 (D) 133 (E) 134 【答案】 D 【思路】 380TS, T=5代入 4003S,S so, the maximum number of students possible in the course that has 5 teaching assistants=133 33. 4484!item!187。 058amp。 004004 If x^4 + y^4 = 100, then the greatest possible value of x is between (A) 0 and 3 (B) 3 and 6 (C) 6 and 9 (D) 9 and 12 (E) 12 and 15 【答案】 B 【思路】 443 100 又 ,所以 the greatest possible value of x is between3 and 6 34. 4586!item!187。 058amp。 004030 Of the following, which is least? (A) (B) ()2 (C) (D) (E) 35. 4632!item!187。 058amp。 004107 What is the sum of the different positive prime factors of 550 ? (A) 10 (B) 11 (C) 15 (D) 16 (E) 18 【答案】 E 【思路】 550=5x5x2x11 the sum of the different positive prime factor=5+2+11=16(5只能加一次因為 different) 36. 4841!item!187。 058amp。 004235 In a certain deck of cards, each card has a positive integer written on it. In a multiplication game, a child draws a card and multiplies the integer on the card by the next larger integer. If each possible product is between 15 and 200, then the least and greatest integers on the cards could be (A) 3 and 15 (B) 3 and 20 (C) 4 and 13 (D) 4 and 14 (E) 5 and 14。