PP-Test2-DS-176

[chris8888]

176. 17259-!-item-!-187;#058&011402
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 ?
不確定這樣算對嗎? 不過應該是這樣, 不對請修正一下
(1) In 1995 the overall service-error rate for Divisions A and B combined was 1.5 service errors per 100 customers.
(86 + Y-service-errors)/(4850 + Y-customer) = 0.015
兩個未知數, insufficient
(2) In 1995 Division B had 9,350 customers, none of whom were customers of Division A.
(86 + Y-service-errors)/(4850 + 9350) = Total-rate
還是兩個未知數

1+2.
(86 + Y-service-errors)/(4850 + 9350) = 0.015
Y-service-errors = 127 errors / per 100 customers

Answer : C