Question 97126
e+f=58 or e=58-f
(e+10)=f+10
2(58-f+10)=f+10
116-2f+20=f+10
-2f-f=10-20-116
-3f=126
f=-126/-3
f=42 age of the father 10 years ago.
e=58-42
e=16 age of Eric 10 years ago.
proof
42+16=58
also
2(58-42+10)=42+10
2*26=52
52=52