大家帮帮我

shining_spags

 

1If p and n are positive integers and p>n, what is the remainder when p^2-n^2 is divided by 15?

(1)    The remainder when p+n is divided by 5 is 1

(2)    The remainder when p-n is divided by 3 is 1

Answers: E

 

 

是怎么一个思路呀

 

 

 

 

2 Of the 60 animals on a certain farm, 2/3 are either pigs or cows. How many of the animals are cows?

(1) The farm has more than twice as many cows as it has pigs.

(2) The farm has more than 12 pigs.

Answer: C

 

 

我觉得题目（1）说明2/3是cows 但是（2）也哪说明pigs 数目应该也不行呀，因为从（1）只知道pigs <1/3

怎么做呢

 

 

3 if the integers a and n are greater than 1 and the product of the first 8 positive integers is multiple of a的n 次方， what is the value of a?

(1) a的n次方=64

（2）n=6

Answer: B

两个问题

1 怎么做

2 first 8 positive integers 是指从1到8还是就是随便8个数

 

 

1If p and n are positive integers and p>n, what is the remainder when p^2-n^2 is divided by 15?

(1)    The remainder when p+n is divided by 5 is 1

(2)    The remainder when p-n is divided by 3 is 1

Answers: E

 

 

是怎么一个思路呀

 

 

 

 

2 Of the 60 animals on a certain farm, 2/3 are either pigs or cows. How many of the animals are cows?

(1) The farm has more than twice as many cows as it has pigs.

(2) The farm has more than 12 pigs.

Answer: C

 

 

我觉得题目（1）说明2/3是cows 但是（2）也哪说明pigs 数目应该也不行呀，因为从（1）只知道pigs <1/3

怎么做呢

 

 

3 if the integers a and n are greater than 1 and the product of the first 8 positive integers is multiple of a的n 次方， what is the value of a?

(1) a的n次方=64

（2）n=6

Answer: B

两个问题

1 怎么做

2 first 8 positive integers 是指从1到8还是就是随便8个数

 

 

shining_spags

谢谢楼主&nbsp; ！！！！！！

yangjuan228

一，1，p+n =5A+1》n=5A+1-p>p^2-n^2=(5A+1)(2p-5A-1)

   2,同1也得不出

   1+2》带具体数字进去，余数也有很多不同

二，1，c>2p

  2，p>12

不等式联力求解（加上题目条件种还有2/3）

三，first 8 positive integers 是指从1到8
1，求不出

2，n=6>a=2