Here's another one for you

My other riddle in epic's thread was pwned quickly, try this one

The child is 25 years younger than the mother.
In 7 years, the mother will be five times as old as the daughter.
Where is the father?

Good luck ;) Once someone finds out how this works, I'll post the solution here.

Solution, clicky.
X is the mother and Y is the child.

Y + 25 = X

X + 7 = (Y + 7) * 5


So now we have
X = Y + 25
X + 7 = (Y + 7) * 5

That means we can replace X with Y + 25.

X + 7 = (Y + 7) * 5
becomes
Y + 25 + 7 = (Y + 7) * 5
<=>
Y + 32 = Y*5 + 7*5
<=>
Y + 32 = Y*5 + 35
<=>
Y = Y*5 + 35 - 32
<=>
Y = Y*5 + 3 // now we do - Y on both sides
<=>
0 = Y*4 + 3
<=>
-3 = Y*4 // divided by 4...
-0,75 = Y

That means the child is -0,75 years old... She will be born in 9 months. Where are fathers usually 9 months before a child is born? ;D Right, on top, as you found out correctly.

Crossfire learned their maths :D