The ratio of ages of the father and mother was 11 ∶ 10 when their son was born. The ratio of ages of the father and mother will be 19 ∶ 18 when the son will be twice his present age. What is the ratio of present ages of father and mother?
1
15 ∶ 14
2
14 ∶ 13
3
16 ∶ 15
4
17 ∶ 16