Question 713109
Let, Lacy's age is = X
so, after 6 year, her age will be = X+6
Jack's age is two times as old as Lacy = 2*X = 2X
after 6 years, his age will be = 2X+6

According to the question:
=> X+6+2X+6 = 30
=> 3X+12 = 30
=> 3X = 30-12
=> 3X = 18
=> X = 18/3
=> X = 6
Lacy's age is = 6
Jack's age is 2*6 = 12
          Answer: Lacy's age is 6 years old and Jack's age is 12 years old.