Sameer is three times as old as his daughter. Four years ago he was seven times as old as she was then. How old is the daughter NOW (in years)?

Let the daughter be $x$ years old now, so Sameer is $3x$. Four years ago: $3x-4=7(x-4)$ → $3x-4=7x-28$ → $4x=24$ → $x=6$. Check: four years ago they were 14 and 2, and $14=7\times 2$. The trap 18 is Sameer's present age and 2 is the daughter's age four years ago — the question asks for her age today.