Question

A girl is twice as old as her brother and half as old as her dad. in 22 years, her brother will be half as old as his father. how old is the daughter now?

Answer 1

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).