Parrallelogram with given ratio

Question

Points $X$ and $Y$ are taken on the sides $QR$ and $RS$, respectively of a parallelogram $PQRS$, so that $\vec QX:\vec XR =4:1$ and $\vec RY :\vec YS=4:1$ . The line $XY$ cuts the line $PR$ at $Z$ we have to prove $PZ=(21/25)PR$.

I am not getting anysta4t .

Can anybody provide me a hint .

Answer 1

Hint: take the simplest case, that of PQRS being a square. Once you've proved it for a square, can you prove it for a rectangle? Once you've proved it for a rectangle, can you prove it for a parallelogram?