To answer this question, you need to turn the description into an equation. If F is the father and D is the daughter, the equation would be:
1. (F-6)= 13(D-6)
F-6 = 13D -78
2. F= 7D
D= 1/7F
If you put the 2nd equation into the 1st equation, you can determine the movie star(father) ages. The calculation would become:
F-6= 13(1/7F)- 78
F-6 + 78=13/7 F
13/7F - F= 72
6/7F= 72
F= 72 *(7/6)= 84 years
