标题: 这道题不理解，请指教 [打印本页] 作者: 飞行2010 时间: 2010-2-8 20:43 标题: 这道题不理解，请指教 176.In 1995 Division A of Company X had 4,850 customers.If there were 86 service errors in Division A that year, what was the service-error rate, in number of service errors per 100 customers, for Division B of Company X in 1995 ?
(1) In 1995 the overall service-error rate for Divisions A and B combined was 1.5 service errors per 100 customers.
(2) In 1995 Division B had 9,350 customers, none of whom were customers of Division A. 题目读得糊里糊涂的，请大家帮我分析下，辛苦了。 作者: Soulmaster 时间: 2010-2-8 22:24
(86+b)/(4850+9350)=0.015 b=127 b/9350=1.36%