Concept:If we divide any A.M element with any continuous number (except 0) then the new A.M will always divisible by that number. Given:In A.M of series of item, we subtract a from every item and divide every item by 'bCalculation:Let,Item = x, And number of terms in the series is 'n'.Then,It average mean is nx.Here,Subtract a from every item and divide every item by 'b.Then,? \(\frac{nx~-~na}{nb}\)? \(\frac{x~-~a}{b}\)So, We can say that the new A.M of series of item is diminishes by a and divided by b.