求教3道数学题(题看不大懂，谢谢)

aj90110

1.
Is S is the infinite sequence
S1=9 , S2=99 , S3=999....Sk=10的k次方 -1
Is every item in S divisible by the prime number P?
(1) P is grater than 2
(2)At least one term in sequence S is divisible by P
答案：E

2.
Terry and Pat collected cans for recycling. What was the ratio of the number of cans Terry collected to the number of cans Pat collected
(1) Pat collected 50 percent of the cans that they collected
(2) Terry collected 140 cans
答案：A

3.
If the length of each side of rectangle R is squared, what is the sum of the four squared length?
(1) The diagonal of rectangle R has length 15
(2) The product of the length of two adjacent sides of rectangle R is 108
答案：A


不知是答案错误还是算错
请求各位大侠支援

liyingcai1988

第一题: 3和11都是满足两个条件的数..但是3可以整除所有item..11不能..
第二题: 题目说T和P两个人收集罐子做回收,问T收集到的罐子数量和P收集到的罐子数量的比值是多少..
           A选项就知道了P收集了(P+T)总数的一半..就知道P和T收集的数量一样了..
第三题: 如果长方形R的每边都平方了,他们的平方和是多少?
           A选项. 对角线的平方等于两个临边的平方和..所以知道对角线就知道临边平方和了..就知道总的平方和了..