扫描二维码，直接登录
题库 / OG2017Q-DS-236
Each Type A machine fills 400 cans per minute, each Type B machine fills 600 cans per minute, and each Type C machine installs 2,400 lids per minute. A lid is installed on each can that is filled and on no can that is not filled. For a particular minute, what is the total number of machines working?
(1)A total of 4,800 cans are filled that minute.
(2) For that minute, there are 2 Type B machines working for every Type C machine working.
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
题目分析：
设A类型的机器有a台，B类型机器b台，C类型机器c台。其中A、B灌装，C盖盖子。由于题目中说明，所有灌装的罐子均被盖盖子，因此，有400a+600b=2400c，本题求a+b+c的值。
（1） 一分钟总共灌装4800罐，所以有400a+600b=4800，代入得2400c=4800，解得c=2。无法得知a、b的值，所以仅根据条件1无法确定a+b+c的值。
（2） B类型的机器是C类型的两倍，所以b=2c。只有条件2也无法确定a+b+c的值。
结合条件1和条件2，c=2，b=2c=4，代入400a+600b=4800，解得a=6，所以所有的机器总数为a+b+c=2+4+6=12台。题目得解。
因此，本题答案为（C），两个条件结合起来才能解题，任何单独一个均不行。
A lid is installed on each can that is filled and on no can that is not filled.
登录 或 注册 后可以参加讨论