[讨论 有2道数学题，请牛人们帮忙看看！

liuyunyao833

1.If d = 1/（2*2*2*5*5*5*5*5*5*5） expressed as a terminating decimal, how many nonzero digits will d have?

 

A.   One

B.   Two

C.   Three

D.   Seven

E.    Ten

2.Of the 60 animals on a certain farm,  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.

              

2.Of the 60 animals on a certain farm,  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.

              

jjj_kkk_kkk

d = 1/（2*2*2*5*5*5*5*5*5*5）

把2*5=10作为一对，剔除，因为1除它们只是加了一个零而已。那么剩下1/(5*5*5*5)=0.0016  so B

p=pigs, c=cows, p+c = 60
(1) c = 2p 代入联解 p=20 c=40
(2) p>12, 不能解出唯一答案。为保险，试验特殊值： p =20 c=40; p=40 c=20都可以。

所以答案是A。

liuyunyao833

呵呵，谢谢啦！！！！！

xz328

more than twice as many cows as。 应该是至少两倍吧。也就是说大于等于。 所以有异议