To install cable television in a home, a certain cable company charges a basic fee of $30 plus a fee of $20 for each cable outlet installed in the home. How much did the cable company charge the Horace family for installing cable television in their home?
(1) The cable company installed three cable outlets in the Horace family home.
(2) The amount that the cable company charged the Horace family for installing cable television in their home was equivalent to an average (arithmetic mean) charge of $30 per cable outlet installed.
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.
很简单 不要轻易出错 看清楚题目
average (arithmetic mean) charge of $30 per cable outlet installed要怎么翻译阿
就是装cable的平均值是30,用装cable的总费用除以cable的数量,等于30。可以得出cable的数量,也就有总费用了。
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(1) The cable company installed three cable outlets in the Horace family home. Total cost=$30+$20*3. Sufficient.
(2) The amount that the cable company charged the Horace family for installing cable television in their home was equivalent to an average (arithmetic mean) charge of the $30 per cable outlet installed. Say the number of outlets is x, then Total cost=$30+$20*x and the average is ($30+$20*x)/x --> ($30+$20*x)/x=30. We can solve for x. Sufficient.
(30+20*X)/x=30 ,x=3
基本费用是不变的,即永远只有一个30,20的个数是随着插头安装的数目增加。
2可以求出安装了多少台,再用题目给出的条件算总共花费
(2)(30+20*X)/x=30 所以条件2单独成立
只装了一家人!!!!!!!!