A， Find the value.....

求和公式：=(2/9)*(1-1/(n+1))  n=2007/9, 所以结果是223/1008

B,Evaluate.......

同样求和：9+1+1/2-1/n-1/(n+1)， n=10, 所以结果是10+17/55

1.  The product of n whole numbers 1 x 2 x 3 x 4 x 5 x …x  (n-1) x n has twenty eight
     consecutive zeros. Find the largest value of n.

乘到100是24个零了（有用的小常识），所以到120就有28个零了，n最大就是124


2. How many ways are there to distribute 28 identical marbles into 3 different boxes such
that no box is empty?

排列组合，计算C27 2 （上下标）就可以了，结果是351

3.  Find the largest number n such that there is only one whole number  k that satisfies
                                    8/21 < n/(n+k) < 5/13
     (Note: A<B<C means that value of B is between A and B)

转换：40/105<n/(n+k) < 40/104  =   80/210 <n/(n+k) < 80/208  即可知n=80 时，k=209-80=129，满足条件且k为唯一整数

4. Give that (200820082008…2008623) / (n of 2008), find the smallest value of n such that
    the number is divisible by 11.

题目没看明白啊，汗，只知道要让11除尽，该数的偶数位加起来等于奇数位就行了。。。

中午匆忙一做，发现3题做反，改过，

[ 本帖最后由 Betty老豆 于 2009-3-26 14:46 编辑 ].

聪明的宝宝，开心的妈妈.