2023 · Q9
The sum of deviations of n numbers from 10 and 20 are a, b respectively. If b/a = −4, then what is the mean of these n numbers?
Elementary MathematicsStatistics
- A12
- B14
- C16
- D18
Explanation
Sum(xi-10)=a and Sum(xi-20)=b give 10n=a-b. With b=-4a, 10n=5a, a=2n. Mean=(a+10n)/n=12. Option (a).