从小数学就不好的人 12月12号就要考试了 最后的挣扎 prep数学求助

aihuge1000

本人从小数学就不好 我不会的题 在大家看来可能很简单 所以麻烦大家帮我解答一下 马上就考试了 GMAT的数学题 稍微超过小学水平一点的 我基本都不会 很害怕 谢谢啦

１．If C and D are integers,is C even?
       (1)C(D+1)is even
       (2)(C+2)(D+4)is even
答案选C 不明白


2. What is the average height of n people in a group?

(1)The average height of the n/3 tallest people in the group is 6feet 2.5inches,and the average height of the rest of the people in the group is 5 feet10inches.

(2)The sum of the  heights of the n people is 178 feet 9 inches

答案选A 我觉得选D 啊 （2）怎么不对了呢


3.What 's the greatest possible area of a triangular region with one vertex at the center fo a circle of radius 1and the other 2 vertices on the circle.
   A 根号3/4    B1/2     C π/4    D1    E 根号2
答案选B 完全没思路


4.  Five pieces of wood have an average length of 124 centimeters  and a median length of 140 centimeters.What is the maximum possible length of the shortest piece of wood?
 A 90     B 100        C 130         D  140     E 110
 答案选B  数学盲再次发懵了

lbccd

他极限了

sdcar2010

我觉得第三题sdcar2010 同学解释的有点问题呢，高不可能等于2吧，因为只有切线才和半径垂直，这样的话就不能保证有两边在圆上了

-- by 会员 715676 (2010/12/7 0:09:56)

Vertex, by definition, is the point of intersection of lines or the point opposite the base of a figure.  So vertex is not a line, but a point. In the question you are referring to, the triangle has two points on the circle and one point at the center.  The biggest area occurs when the the triangle is a 90 degree right triangle.

715676

sorry，不可能是1

715676

我觉得第三题sdcar2010 同学解释的有点问题呢，高不可能等于2吧，因为只有切线才和半径垂直，这样的话就不能保证有两边在圆上了

aihuge1000

12号就考试了~别纠结prep了，直接做狗

-- by 会员 肉圓兒 (2010/12/6 10:07:56)

我也是一直在做狗>< 數學很糟糕

-- by 会员 aries740408 (2010/12/6 12:48:00)

嗯 加油 加油 祝我们都考个好成绩

aries740408

12号就考试了~别纠结prep了，直接做狗

-- by 会员 肉圓兒 (2010/12/6 10:07:56)

我也是一直在做狗>< 數學很糟糕

sdcar2010

不好意思 我打错了 应该是2)The sum of the  heights of the n people is 178 feet 9 inches

-- by 会员 aihuge1000 (2010/12/6 10:26:49)

In that case, the average height = 178'9" / n; since n is unknown, the average is unknown.  So 2 is not sufficient.

aihuge1000

非常感谢 麻烦你了

aihuge1000

不好意思 我打错了 应该是2)The sum of the  heights of the n people is 178 feet 9 inches