Average = sum of observations ÷ Total number of observations Calculation Let the number are n,n+2,n+4,n+6 We know that Average = sum of observations ÷ Total number of observations ⇒ Average =
(n)+(n+2)+(n+4)+(n+6)
4
=27 ⇒
4n+12
4
=27 ⇒n=24 Sum of numbers n+(n+2)+(n+4)+(n+6)=27×4 Let x is added to the given number then the average becomes 28 . ⇒