MATH GWD2 Q5 Q6 Q18 Q33

joyzhang1990

请大家帮忙解答下~做错了~可是不知道为什么~跪谢大家~
Q5额，图沾不上来~)
In the figure, points A, B, C, D, and E lie on a line.A is on both circles, B is the center of the smaller circle, C is the center of the larger circle, D is on the smaller circle, and E is on the larger circle.What is the area of the region inside the larger circle and outside the smaller circle?

(1)AB = 3 and BC =2
(2)CD =1 and DE = 4

Q6
The figure above shows the dimensions of a semicircular cross section of a one-way tunnel.The single traffic lane is 12 feet wide and is equidistant from the sides of the tunnel.If vehicles must clear the top of the tunnel by at least ½ foot when they are inside the traffic lane, what should be the limit on the height of vehicles that are allowed to use the tunnel?

A.5½ ft
B.7½ ft
C.8 ½ ft
D.9½ ft
E.10 ft

Q18:
On a certain transatlantic crossing, 20 percent of a ship’s passengers held round-trip tickets and also took their cars abroad the ship.If 60 percent of the passengers with round-trip tickets did not take their cars abroad the ship, what percent of the ship’s passengers held round-trip tickets?
A.33 1/3%
B.40%
C.50%
D.60%
E.66 2/3%

Q33:
In Town X, 64 percent of the population are employed, and 48 percent of the population are employed males.What percent of the employed people in Town X are females?

A.16%
B25%
C.32%
D.40%
E.52%

暂时就这些~错的太恐怖。马上要考了~求大家帮忙分析下~急啊~

joyzhang1990

HELP~~~~

lswvane

我也刚做完~~分享一下我的批注吧：）

Q5  选D
要求面积差只要知道大圆和小圆的半径分别是多少就OK啦~（下面用R和r代替）
(1)    AB=3，BC=2；看图直接能推出：r=3,R=5，大圆面积-小圆面积即可得
(2)    CD=1，DE=4；由图得R=5且2r+4=2R=10，所以r=3，面积差即可得


Q6  选B
画图就能一目了然啦。半圆隧道里面内切一个长方形轨道，轨道长12ft所以一半就是6ft，半圆直径是20ft那么半径就是10ft，连接切点和圆心这时会看到一个直角三角形三边是6、8、10（用勾股定理），题目说车要低于0.5，所以就是8-0.5=7.5啦。

Q18  选C
这种题我每次都自己假定一个总数。
假设一共有100个乘客，由条件可知：有票且自己带车的有20人；有票没带车占有票人数（注意不是总人数）的60%，也就是说有票且带车的占40%；设有票人数为x，那么0.4x=20，求出x=50，占总人数100的50%。

Q33  选B
和Q18一样的方法啦，比Q18还简单点，没那么绕。
假设TOWN X一共有100人。其中64人是有工作的人，48人是有工作的男人，那64-48=16就是有工作的女人啦。那女人占有工作的人百分比是多少就很明显啦：16/64=25%咯。

加油哈

joyzhang1990

好。谢谢你！