Help and tell me how you did it

125% =  1.25

"Of" means "Multiply"

So

1.25n   =30       divide both sides  by 1.25

n = 30/1.25   =   24

25%   =   .25 =  25/100 =  1/4

So

(1/4)  of 24   =    24 (1/4)   =    6