JULY ELECTRICITY USAGE FOR THE SMYTHE HOUSEHOLD[img]ct_gre6image040[/img]The

游客2024-01-12  9

问题 JULY ELECTRICITY USAGE FOR THE SMYTHE HOUSEHOLD


The electricity used by the water heater was measured separately and its cost per kilowatt-hour was one-half the cost per kilowatt-hour of the rest of the electricity used. The cost of the electricity used by the water heater was most nearly what fraction of the total cost of all the electricity used?

选项 A、1/11
B、1/9
C、1/8
D、1/5
E、It cannot be determined from the information given.

答案 B

解析 标题:Smythe家庭7月份的用电分布热水器用的电是分开计算的,它消耗的电的每千瓦/时的价格是其他用电设备的一半。热水器的电费占总电费的比例最接近于下面哪一项?
解:本题的正确答案为(B)。由题干中的饼图可知热水器的用电量占总用电量的20%,而其他各项占总用电量的80%,设热水器的电费为$X千瓦/小时,则其他各项的电费为$2X千瓦/小时,由此可知热水器的电费占总电费的比例为:20%X/(20%X+80%×2X)=1/9
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