The mean of 10 number is 20. If 5 is subtracted from every number, what will be the new mean?

Explanation

Given:
n=`10` numbers
Mean=`20`
Let their sum be `x`
`therefore` Mean=Sum of observations/No of observations
`20=(x)/10`
If `5` is subtracted to each number then the sum decreases by `10xx5 = 50`
∴New Mean = `(x-50)/10= ((20xx10)-50)/10`
`=(200-50)/10=150/10=15`
So, the required new mean is `15`