The present age of the father is twice the sum of the present ages of the son and the daughter. One year ago, the son's age was four less than twice the daughter's age. If after 4 years, the ratio of the age of the father and daughter will be 4:1, then find the age of the son?
1
17 years
2
12 years
3
14 years
4
15 years
5
13 years