As shown in the diagram, BD/DC=2,CE/EA=3, and AF/FB=5. Find [DEF]/[ABC].
Let the area of the triangle ABC be Δ,then 12AB.AC.sinA=Δ.So, since AF=5AB/6,andAE=AC/4,the area of the triangle AFE=12.56AB.14AC.sinA=524Δ.
Over to you.