Answer:
1 : 12 : 4
Explanation:
Let A, G, C represent the ages of Alex, George, and Carl, respectively. We are told that ...
A = G +12
C = 3A . . . . . . . we read this as "3 times as old"; not "3 times older"
A + G + C = 68
Substituting for G and C, we have ...
A + (A -12) +(3A) = 68
5A = 80 . . . . . add 12
A = 16 . . . . . . . divide by 5
The other ages are then ...
G = A-12 = 16 -12 = 4
C = 3A = 3·16 = 48
The ratios are ...
G : C : A = 4 : 48 : 16
G : C : A = 1 : 12 : 4