Question 1035757
Let f be the age of the father NOW and s be the sum of his sons' ages NOW...then we write
f = s - 10  and seven years ago
f - 7 = 3(s - 7)
Now substitute and get
s-10 - 7 = 3(s - 7)
s - 17 = 3s - 21
Subtract s and add 21...we get
2s = 4
s = 2
But that is impossible.
Please repost the problem.