I am not sure on this question can someone please explain and solve for me ASAP

We have proportion:
[tex]\dfrac{|JN|}{|JM|}=\dfrac{|LN|}{|MK|}[/tex]
We have:
[tex]|JM|=8;\ |MK|=40;\ |LN|=30[/tex]
substitute:
[tex]\dfrac{|JN|}{8}=\dfrac{30}{40}\ \ \ |\cdot8\\\\|JN|=\dfrac{30}{5}\\\\|JN|=6[/tex]
Answer: 6