2003 xIMC keystage2-EMIC team Question 1

In quadrilateral $ABCD$, points $M,N,P,Q$ lie on $AB,BC,CD,DA$. Given $AM:MB=3:5$, $BN:NC=1:3$, $CP:PD=4:5$, $DQ:QA=1:8$, find $[MBNPDQ]:[ABCD]$.