求助输血狗～有三个数字70， 200， n，……

happysmiledy

题目：有三个数字70， 200， n，他们任意一个都可以整除divide另外两个数字的乘积。问N的最大可能值和最小可能值之比。
答案：综合一下，最小值的可能是140，最大值的可能是14000。所以比值就是14000/140=100

没看懂……题目不是说任意一个都可以divide另两个数字的乘积吗，
         如果n=140的话，200能整除（70×140）？？？我是不是理解错了……

VenciTan

70=2*5*7
200=2^3*5^2
仨数每一个都能整除另俩积
N=2^2/2^3/2^4*5/5^2/5^3*7
max=5^3*2^4
min=5*2^2

ldu09

”任意一个都可以divide另两个数字的乘积“ 表达是对的～

Note that
A divides B ＝A is divisible by B  =  B is a divisor (factor) of A = A is a multiple of B
e.g.
5 divides 20 ＝20 is divisible by 5 =  5 is a divisor(factor) of 20 == 20 is a multiple of 5

Here any number divides the product of the other two, which means any number is a factor of the product of the other two.

-- by 会员 chinamerica (2010/10/23 4:19:33)

我覺得如果 A divides B＝ B／A
A is divisible by B= B/A
B is a divisor of A=A/B
????不明白了。。。

ldu09

(200＊N)/70
(70*N)/200
(200*70)/N
通過上面的式子可以求出Nmin＝140
通过最后一个式子可以求出Nmax＝14000
所以比例是1／100

chinamerica

sorry,   the first term should be B divides A ..
In the example A=20, B=5
B divides A ＝A is divisible by B  =  B is a divisor (factor) of A = A is a multiple of B
5 divides 20 ＝20 is divisible by 5 =  5 is a divisor(factor) of 20 == 20 is a multiple of 5

guoqiongjiu

”任意一个都可以divide另两个数字的乘积“ 表达是对的～

Note that
A divides B ＝A is divisible by B  =  B is a divisor (factor) of A = A is a multiple of B
e.g.
5 divides 20 ＝20 is divisible by 5 =  5 is a divisor(factor) of 20 == 20 is a multiple of 5

Here any number divides the product of the other two, which means any number is a factor of the product of the other two.

-- by 会员 chinamerica (2010/10/23 4:19:33)

BIG CROSS....A divides B= B is divisible by A=A is a divisor (factor) of B = B is multiple of A

zhipei

”任意一个都可以divide另两个数字的乘积“ 表达是对的～

Note that
A divides B ＝A is divisible by B  =  B is a divisor (factor) of A = A is a multiple of B
e.g.
5 divides 20 ＝20 is divisible by 5 =  5 is a divisor(factor) of 20 == 20 is a multiple of 5

Here any number divides the product of the other two, which means any number is a factor of the product of the other two.

-- by 会员 chinamerica (2010/10/23 4:19:33)

Thanks! Got it.

chinamerica

”任意一个都可以divide另两个数字的乘积“ 表达是对的～

Note that
A divides B ＝A is divisible by B  =  B is a divisor (factor) of A = A is a multiple of B
e.g.
5 divides 20 ＝20 is divisible by 5 =  5 is a divisor(factor) of 20 == 20 is a multiple of 5

Here any number divides the product of the other two, which means any number is a factor of the product of the other two.

zhipei

除，除以~~~英文应该不会混淆吧~~~divide，divided by

-- by 会员 fujianaicd (2010/10/23 0:16:45)

也在想这个题，同不明白
a divide b=a/b
a divided by b=b/a
我这样的理解应该对吧？

此题题目是说“70， 200， n，他们任意一个都可以整除divide另外两个数字的乘积”就应该是 a/(b*c)这种形式啊，怎么会颠倒过来的？？？

zhlee

n最小是140， 最大是14000