Answer:
47 years old.
Step-by-step explanation:
Let c represent each children, 'f' represent the father and 'm' represent the mother. We are given that:
[tex]4c=15*4=60\ years\\f=m+4\\\frac{4c+m+f}{6}=25[/tex]
Replace the first two equations into the last to solve for 'f':
[tex]\frac{60+(f-4)+f}{6}=25 \\2f=(25*6)-60+4\\f=47\ years[/tex]
The father is 47 years old.
