jmc

The area of triangle $EFG$ is $(1/6)(70)=35/3$. Triangles $AFH$ and $CEH$ are similar, so $3/2=EC/AF=EH/HF$ and $EH/EF=3/5$. Triangles $AGJ$ and $CEJ$ are similar, so $3/4=EC/AG=EJ/JG$ and $EJ/EG=3/7$. Since the areas of the triangles that have a common altitude are proportional to their bases, the ratio of the area of $△EHJ$ to the area of $△EHG$ is 3/7, and the ratio of the area of $△EHG$ to that of $△EFG$ is 3/5. Therefore, the ratio of the area of $△EHJ$ to the area of $△EFG$ is $(3/5)(3/7)=9/35$. Thus, the area of $△EHJ$ is $(9/35)(35/3)=\boxed{3}$.