16. In the figure above, y+z=? (A)180 (B)195 (C)215 (D)230 (E)245
18. The figure above shows part of a circle whose circumference is 45. If arcs of length 2 and length b continue to alternate around the ensure circle so that there are 18 arcs of each length, what is the degree measure of each of the arcs of length b ? (A) 4° (B) 6° (C) 10° (D) 16° (E) 20°
20. If the five line segments in the figure above are all congruent, what is the ratio of the length of AC (not shown) to the length of BD ? (A) 2^0.5 to 1 (B) 3^0.5 to 1 (C) 2^0.5 to 2 (D) 3^0.5 to 2 (E)3^0.5 to 2^0..5
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15. In the figure above, EBCD is a square and AE =8 What is the area of EBCD ?
18. In the figure above, if the legs of triangle ABC are parallel to the axes, which of the following could be the lengths of the sides of triangle ABC ? (A)
2.
5.and
29^0.5 (B) 2. 5, and 7 (C)
3,3,and3*2^0.5 (D) 3, 4, and 5 (E) 4, 5, and 41^0.5
类型 4：
18. If the average (arithmetic mean) of x and y is k, which of the following is the average of x, y, and z ? (A)(2k+z)/3
(B)
(2k+z)/2 (C) (k+z)/3 (D) (k+z)/2 (E) 2(k+z)/3
IN A PRESCHOOL
CLASS
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Number of Siblings 0 1 2 3 Number of Students 3 6 2 1 8.The table above shows how many students in a class of 12 preschoolers had 0,1, 2, or 3 siblings. Later, a new student joined the class, and the average (arithmetic mean) number of siblings per student became equal to the median number of siblings per student. How many siblings did the new student have? (A) 0 (B) 1 (C) 2 (D) 3 (E) 4
18. The table above shows student enrollment at Weston High School from 1992 through 1996. If the median enrollment for the five years was 1351, and no two years had the same enrollment what is the greatest possible value for x ?
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【答案】 类型1题号 答案 20 E 14 24 16 D 类型2题号 答案 18 A 6 D 16 3 20 E A C D D 1 E 2,7 C A 16 70 A 3 D 2 D B E C D 18 A 3/8.375 D C E C E A 类型3题号 答案 20 E 18 B 16 E 8 18 E 2,18 B B A C D C E 8 192 A 10 B A D 17 18 20 149 72 E 4/9,.444 C B A C 24 8 B E 11 B B 1.43 D E 1.14 类型4题号 答案 18 A 8 A 18 1350 19 15 16 18 15 20 18 16 8 17 20 8 19 16 17 15 16 8 19 16 15 17 18 15 18 18 14 18 19 17 15 14 17 15 19 16 20 17 17 15 16 0 15 17 14 16 7 18 8 18 7 19 16 19 14 8 19 / 18