Father A is twice the age of the difference in years of the ages of
Father B and Son A, who is one and a half times older than Son B.
Father B is currently twice the age of Son A is going to be when Son B will be double the age he is now.
All of the ages are multiples of five.
How old is Father A?
Here's the solution I meant to post previously.
Let x = age of Son B ,
then 1.5 x = age of Son A .
Now, Son B will be double his present age x years from now, at which time Son A will be 2.5 x years old.
Hence, the current age of Father B = 2(2.5 x) = 5x
It follows then that the age of Father A is :
2( 5x - 1.5 x) = 7x
In summary, the current ages are:
Son B = x
Son A = 1.5 x
Father B = 5x
Father A = 7x
Since all of the ages are multiples of five , then x must be a multiple of 10 ( i.e., x = 10, 20, 30, ...) . But, unless these fathers and sons lived during the time of Abraham and Noah, the only realistic solution occurs when x = 10.
Therefore, the ages are as follows:
SB = 10
SA = 15
FB = 50
FA = 70