2012年AMC8竞赛真题(英文版)及答案
1. Riichelle uses 2 pounds of meat to make 8 hamburgers for her family. How many pounds of meat docs she need to make 24 hamburgers for a neighborhood picnic?(A) 6(B)g1(C) 71(D)8(E)92. Inhe county of East Westmoro. statisticians estim弑。there is a baby born every 8 hours and a death everir day. To the nearest hundred, iio- many people are addtnl U)Ilie |H)pulaEiuu of 卜工4l VVeslmoie <fach yv;u?(A) GOO (B) 700(C) 800(D) 900(E) 10003. On February 13 The Oshkosh Northwester listed the length of daylight as 10 hours and 2-1 minutes, the sunrise as G:57 am, and the suruet as 8:15 PM. The length of daylight and sunrise were correct? but the simscl was wrong. When did the sun really set?(A) 5:10 pm (B) 5:21 pm (C) 5:11 pm (D) 5:57 i>m (E) G:03 pmo4. Exeter s family ordered a 12-slice pizza for dinner. Peter ate one slioe and shared another slier equally with his brother Paul. Whit fraction of the pizza did Peter cat?(A)i (R)/ (c)i (叭(e)35. In the diagram, all angles are right angles and the lengths of the sides ar e given in centimeters. Note the diagram is not drawn to scale. What is X in centimeters?22n-?211(A) 1(B)2(C)3(D) 4(E) 5G. A rectangular photograph is placed ii)a frame that fbnns a border two inches wide oil all sides of the photograph. I he photograph 11KMstirg 8 inches high and 10 inches wide. What is the area of the borde-r, in. squire inches?(A) 36(B) 40(C) 64(D) T> (E) 887. Isabella must take four 10()-point tests in her math class. Her goal M to adiieve an average grade of at lea5t 95 on the tests. Her first twe test scores were 97 and 91. After seeing her score on the third test, she realized that she could st ill rcadi her goal. What ih the lowest poesiblc score she could have made on the third Lest?(A) <K)(B) 92(C) 95(D) 96(E) 978. A shop advertises, that everything is “half price in today x sale/In addition, a coupon gives a 20% discount on sale prig. Using the cou?on> the price today represents what percentage decounL off the original price?(A) 10(B)(C) 40(D) 60(E) 70(A) 5V巧(B) 10(C> 10v(D)50(E> 50v9. The Fort Worth Zoo has a number of two-legged birds and a number of four- legged mammal,On one visit to the zoo. Marpe counted 200 heads and 322 I。穿.How many of the animals that largie counled were tvo-kgged birds?(A) 61(B) 122(C) 139(D) 150(E) 1G1京410. How many 4-digit numbers greater than 1(XM) are there that uso the four digits of 2012?(A) 6(B) 7(C)8(D) 9(E) 1211. I he mean, median, and unique mode of the positive integers 3, 4, 5, 6, G. 7. i are al) qual. What is the value of z?(A) 5(B) 6(C)7(D) 11(E) 1212. What is thuainig &西t of I32oia?(A)1(B)3(C)5(D)7(E)013. J;nnar bought some pencils costing more than a penny each at the school bookstore and paid $1.43 Shiirona bought wine of the same pencils and paid §1.87. How many more pencils did Sharona buy than Jaiiuir?(A) 2(B)3(C)4(D) 5(E) G14. In the H1G N. a middle school fool ball conference, each teai plays every other team exactly once. If a total of 21 conference games were played during the 2012 season, how many teams were members of the BIG N conference?15. Th4? smallest number than 2 that leaves a remaindpr of 2 when divided by 3, 4 5, or 6 lies between what numbere?(A) 40 and 50(B) 51 and 55(C) 3G and GO (D) Cl and G5(E) 66 and 9916. Each of the digits 0. 1. 2. 3. 4. 5, C. 7. 8. and 9 is med ojily once to make two five-digit numbers (hat they have the largest pwible uin. Which of the following could be one of the number?(A) 76531(B) 86724(C) 87431(D) 96240(E) 9740317. A square with an integer side length is cut into 10 squares, all of which have integer side length and. at least 8 of which have area 1. What is the smallest possible value of the length of the side of the original square?(A) 3(B) 4(C)5(D) G (E) 718. What is the smallest positive integer that in neither prime nor square and that has no prime factor less than 50?(A) 3127(B) 3m (C) 3137(D) 3139(E) 314919. in a jar of red, green, and blue marbles, all but G are red marbles, nil but 8 are Kreeii. and all but 4 are blue. How many marbles are in the jar?(A) 6(B) 8(C> 0(D) 10<E) 182(). What is the correct ordering of the three numbers /, 广.and 会.in increasing order?小 975570.957(A) 23 < 21<19(B) T9 2?23( 方而百s 97-759(D)1g<23<21(E> 21 < 19 < 2321. Maria has a large white cube that ha& an edge of 10 feel. She also has enough gr(n paint to cover 300 square feet. Marla all the paint to creato a white square center on each face, surrounded by a gr«n bordx. W hat is the area of one of the white squares, tn square feet?22. kt /? be a of nine distinct integers. Six of the element of the set are 2. 3.-I. & 9. and 14. What is the number of poKsihle values of the median of RI(A) 4(B)5(C) 6(D) 7(E) 823. An equilateral triangle and a regiiiai hexagon have equal p?rimetere. I