5. Point $M$ divides side $B C$ of parallelogram $A B C D$ in the ratio $B M: M C=1: 3$. Line $A M$ intersects diagonal $B D$ at point $K$. Find the area of quadrilateral $C M K D$, if the area of parallelogram $A B C D$ is 1.
Answer: $\frac{19}{40}$.

## Grading Criteria for the Final Round of the Rosatom Olympiad 04.03.2023, 9th Grade

In all problems, the correct answer without justification $\quad 0$