GWD第1套和第2套数学有几道题不懂希望大侠给予指点。

kurtsniper

第1套Q16 If J,S, and V are points on the number line, what is the distance between S and V?
        (1)The distance between J and S is 20.
        (2)The distance between J and V is 25.
答案给的是E，我不明白为什么是E啊，（1）+（2）完全可以求出来啊。需要详细解答过程，跪谢！


Q22 In the sequence 1,2,4,8,16,32,...,each term after the first is twice the previous term. what is the sum of the 16th,17th, and 18th terms in     the sequence?
        A. 2^18
        B. 3(2^17)
        C.7(2^16)
        D. 3(2^16)
        E. 7(2^15)
需要详细解答过程，跪谢！


Q28 For any positive integer n, the sum of the first n positive integers equals [n(n+1)]/2. what is the sum of all the even integers between     99 and 301?
        A. 10,100
        B. 20,200
        C. 22,650
        D. 40,200
        E. 45,150
需要详细解答过程，跪谢！


第2套
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 did not take their cars abroad the ship, what percent of the ship's passengers held     round-trip tickets?
        A. 33又1/3%
        B. 40%
        C. 50%
        D. 60%
        E. 66又2/3%
需要详细解答过程，跪谢！请把算式写出来吧。


Q27 In a corporation, 50 percent of the male employees and 40 percent of the female employees are at least 35 years old. If 42 percent of     all the employees are at least 35 years old, what fraction of the employees in the corporation are females?
        A. 3/5
        B. 2/3
        C. 3/4
        D. 4/5
        E. 5/6
需要详细解答过程，跪谢!!


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%
        B. 25%
        C. 32%
        D. 40%
        E. 52%


题目有点多，小弟数学确实不太好，希望各位牛牛帮帮我，先谢谢了！！

tinahuang95

1、求不出来
你画一条数轴，从左到右可以为S，J，V 所以SV=45
也可以为J,S,V 所以SV=5
也可以为V.S.J

2、找规律  Y=2^(X-1)
Y16=2^15;Y17=2^16;Y18=2^17
S=(2^15)*7

这些题目都不难吧
我先抛砖引玉2道

kurtsniper

前两道题明白了，为什么你一解释我就明白，自己却怎么也想不出来。后面的大侠能不能也给点提示啊？