Statistics

[cceci]

Could You help me with following ?:

Last year the average (arithemitc mean) salary of 10 employees of Company X was $42.800. What is the average salary of the same 10 emplozees this year?

1. For 8 of the 10 employees, this years salary is 15% greater than last years salary
2. For 2 of the 10 employees, this years salary is the same as last years salary.

[vineeshp]

Answer is E.

1) We dont know the salaries of the other two. Nor do we know their salaries last year to take 15%. Not sufficient.

2) we dont know salary of other 8. nor do we know what their salaries were last year.

1 and 2 ) We still do not know what was the salary last year to add 15% to that.

So E.