Question 27799
Her sister's age 2 years ago = x 
Ben's age = 3(x-2)


One year from now:
x+1= (her sister)
Ben's 3(x-2)+1


2(x+1)-1=3(x-2)+1
2x+2-1=3x-6+1
2x+1=3x-5
-x=-6
x=6


3(6-2)
3(4)=12


Hence, Ben is 12 years old and her sister is 6 years old.