Given,
AM of y numbers = x.
Let the sum of y numbers be s.
AM of y numbers = x
[tex] \frac{s}{y} = x[/tex]
[tex]s = y*x[/tex]
Given, when 30 is added to the y numbers, the AM becomes x - 5.
[tex] \frac{s + 30}{y + 1} = x - 5[/tex]
[tex] \frac{y*x + 30}{y +1} = x - 5
[/tex]
[tex] y*x + 30 = (x -5)( y +1) [/tex]
[tex]y*x + 30 = y*x + x - 5y -5[/tex]
[tex]5y = x - 5 -30 = x - 35
[/tex]
[tex]y = \frac{x -35}{5} [/tex]
