红霞美国数学题1(答案)

2020年11月28日发(作者：冀淑英)
美国数学题1
1、Timothy is building a model of Pentagon(五角形).The actual Pentagon outside
Washington ,D.C. has exterior walls(外墙) that are approximately 920 ft. long. The building has an
interior courtyard(庭院) also shaped like a regular pentagon, and each wall is approximately 360
ft. long. Timothy is using a 9 in. board for one outside wall of the model. What will be the
approximate perimeter of the interior pentagon in his model?（2013-08）
解：920:360=9:x,x=3.52,3.52×5=17.6 in. (17.6 in.)


2、Jan is making a 3-tier(层) wedding cake for 300 guests. She will make the cake for $$3 per
serving with the following specifications(规格):
﹒Each serving is 4 in.
3
.
﹒Each tier must be smaller than the tier below it..
﹒Each square tier is 4 in. tall with a side length of 16 in.,14 in.,12 in.,10in., 6 in..
What is the cost of the most economical(经济的，合算的) 3-tier cake that will serve 300 people?
解：选择12,10,8这一组最合算，
因为12×12＋10×10＋8×8=308,308×4=1232 in.
3

1232÷4=308,308×3=924.（$$924）

3、The Brock family uses a 12-cup coffee maker(咖啡壶), which leaks(渗漏). For every 6 cups of
brewed(冲泡), 1/12 cup leaks out. Mrs. Brock makes a full pot. If 4 coffee drinkers receive the
same amount, how many cups (use a mixed number)will each individual(每个人) receive?
解：12－2×1/12=11 5/6
11 5/6 ÷4= 2 23/24

4、Find a value for each letter in the number sentence if each letter is represented(代表) by a
different positive interger :

T M I
O L
＋
L
T G I
解：答案不唯一，可以如下：
1 2
3
＋
9
1



0 6
F
6
9
5