Hi,
i am 2/3 the age of my brother. mum is three times as old as him
Let x , 2/3x, 3x represent brother, You and mother respectively
Question states*** mum is 3 years younger than Dad(57)..mum is 54
3x = 54
x= 18, Your brother's age. You are (2/3)18 = 12 years old