Let x = the age of the older son.
Let y = the age of the younger son.
a man, when asked the ages of his two sons, replied that
18 more than the sum of their ages
which is:
(x+y)+18
is double the age of the older
which is
2x
So
(x+y)+18 = 2x
Six less than the difference of their ages
which is
(x-y)-6
is the age of the youngest.
which is
y
So
(x-y)-6 = y
what are their ages
Simplify and solve this system of equations
for x and y.
Edwin