Question 3071
Let the father's age be x
then ali's age will be x-30 ( as ali is 30 yrs younger then his father)

Now their combined age is 80
=> x + (x-30) = 80
=> 2x -30 = 80
=> 2x = 110
=> x = 55

So Father's age is 55
and ali's age is 55-30 = 25