Problem 23

In the quadrilateral $PQRS$, the points $M$ and $N$ are marked on sides $PQ$ and $RS$ respectively so that $PM = MQ$ and $SN = 2NR$. The area of triangle $MQR$ is $2\mathrm{m}^2$, and the area of triangle $PSN$ is $6\mathrm{m}^2$. What is the area of quadrilateral $PQRS$?