1.问2(10^n)+y 能不能被3整除？
条件⼀：n>6 条件⼆：2+y 能被3整除
2.(n+9)!/[(n+10)!+(n+9)!] 等于1/4!，问n=？
3.总共50个⼈，没有电脑的占20%，没有⼿机的占18%，什么都没有的有3个 ⼈。问又有⼿机又有电脑的有多少⼈？
4.x,y都是正整数 能否判断x是不是偶数？ 条件⼀：2x+y=odd 条件⼆：5x+3y=odd
5.a+b 是35倍数，求a+b 条件⼀：a=5m+1
条件⼆：B=7n+3
6.有⼀个marble ball半径为r, ⼀个圆柱形花瓶底部半径为 4r, 瓶内有⽔⾼度为 H1, 将n个ball投⼊⽔中,瓶内⽔的⾼度上升⾄H2, 问如何⽤ r, n 表⽰H2-H1
7.正⽅体体积是否⼤于25？ 条件⼀： 表⾯积等于54
条件⼆：所有边长加起来等于36
8.numbers, 20, 30, x (not necessarily to follow this order). is mean smaller than range? 条件⼀： x is smaller than 10
条件⼆：x is greater than 5
9.In xy plane, a circle has its center at origin,and it passes (2, 3),what is the area of the circle.
10.There is a theater with parking lots. it has 17 rows. The first row has 20 lots, the second row has 21 lots, and then each rows behind the 2nd row has 2 more lots than the previous row. How many lots are there in the parking area?
参考答案： 1.B 2.13 3.34 4.C 5.E 6.H2-H1=nr/12 7.D 8.A 9.13派 10.596
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发表于 2021-7-15 16:44:06
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