Answer :
Let x be the age of the brother, then:
Now:
x = brother
2x = sister
4x = father
In 22 years:
(x+22) = brother
(4x+22) = father
4x+22 = 2(x+22)
4x+22 = 2x + 44
4x-2x = 44 - 22
2x = 22
x = 11 years old (brother now)
11*2=22 years old (sister now).
Now:
x = brother
2x = sister
4x = father
In 22 years:
(x+22) = brother
(4x+22) = father
4x+22 = 2(x+22)
4x+22 = 2x + 44
4x-2x = 44 - 22
2x = 22
x = 11 years old (brother now)
11*2=22 years old (sister now).