last-10-2-17

swimmingfrog

17(E).   Certain instruments used in veterinary surgery can be made either of stainless steel or of nylon. In a study of such instruments, 10 complete sterilizations of a set of nylon instruments required 3.4 times the amount of energy used to manufacture that set of instruments, whereas 50 complete sterilizations of a set of stainless steel instruments required 2.1 times the amount of energy required to manufacture that set of instruments.

If the statements above are true, each of the following could be true EXCEPT:

(A) The 50 complete sterilizations of nylon instruments used more energy than did the 50 complete sterilizations of the stainless steel instruments.

(B) More energy was required for each complete sterilization of the nylon instruments than was required to manufacture the nylon instruments.

(C) More nylon instruments than stainless steel instruments were sterilized in the study.

(D) More energy was used to produce the stainless steel instruments than was used to produce the nylon instruments.（B）

(E) The total cost of 50 complete sterilizations of the stainless steel instruments was greater than the cost of manufacturing the stainless steel instruments 10 complete sterilizations of a set of nylon instruments required 3.4 times the amount of energy used to manufacture that set of instruments,
那么1complete sterilizations of a set of nylon instruments required 0.34 times the amount of energy used to manufacture that set of instruments,
所以B肯定错，而其他的则不一定.

还是不能读懂这道题目

chelseayang

Stimulus anaylysis:

Nylon instrument: 10 (times of) sterilizations = 3.4 x manfacture energy (of a nylon set)

Stainless instrument: 50 sterilizations = 2.1 x manufacture energy (of a stainless set)

注意, 我们不知道NYLON 和STAINLESS 各自的manufacture energy

剩下的工作就是运用基本的数学知识就可以答题了

如果我还没有讲清楚， 请跟贴

swimmingfrog

明白了nylon's   .manufacture energy :sterilization energy=1:0.34

只是到了考场上我就晕菜了我.

不过我又搞不懂C 了.数量是怎么得出来的

E也有问题啊,不知道单价,怎么知道total cost啊?

chelseayang

the question is "what is could be true"

swimmingfrog

nod ,唉,又没仔细看问题!

Bensontuo

swimmingfrog 发表于 2004-12-7 04:11
17(E).   Certain instruments used in veterinary surgery can be made either of stainless st ...

energy to produce 10 of n = 3.4 of n

energy to produce 50 of s = 2.1 of s

Do we know exact unit of energy required to produce single unit of n and s ? No

By lacking the answer above, can we compare the variance of times, energy cost, and efficiencies ? no

* Question ask for " must be false "

A. It could be true and could not be true.

B. Must be wrong.  STER of nylon instrument = 0.34 / set

c. do we know how many of nylon instruments per set of sterilizations ?No, so it could be true and also could not be true.

d. Could be true and could not be true

E. could be true and could not be true.