service errors

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by ajith » Wed Apr 21, 2010 3:25 am
nisha.menon294 wrote:can some one explain why a is not sufficient
Error rate per 100 customers = No of errors / Total Customers *100

Stem says A has 4850 customers and 86 errors
Say division B has x customers and y errors

Statement 1: (86+y)/ (4850+x) *100 = 1.5

Insufficient - 2 variables and 1 equation

Statement 2: x = 9350

Insufficient

Combining we can find out y and the error rate, hence C
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by gmatmachoman » Wed Apr 21, 2010 10:31 am
nisha.menon294 wrote:can some one explain why a is not sufficient
I surmise u wuld have done this mistake:

service error rate of A +Service error rate of B = 1.5As we know value of A, u thought we can get B...( even same way i thought... But there is a catch word "combined")

Later it was like using Average speed formulae: total distance /total time taken...

{(86+y)/(4850+x) } * 100 = 1.5

from st2, we get value of x( number of customers of B)....

then we can find Y....then find {y/x }*100