a certain city with a population of 132,000 is to be devided into 11 voting districts, and no district is to have a population that is more than 10 percent greater than the population of any other district. What is the minimum possible population that the least populated district could have? 10,700 10,800 10,900 11,000 11,100 答案是d 最小的那个是一个最小的,10个比最小的大10%的 If x, y and z are intergers and xy+z is an odd interger, is x an even integer?
1. xy+xz is an even integer
2. y + xz is an odd integer 答案是a 两个相减z(x-1)奇数,两个都是奇数,所以知道x偶数 相减(x-1)(y-z)偶数,不能确定 | 
