It will be the last one since it is the one that makes more sense.
Since 30 lights are 40% of them:
30*2= 60
Since 2*40= 80
We still need the 20 percent.
Half of 40= 20.
30/2= 15
So, 15+60= 75
75 is the number of lights on the tree.
I hope this helps!
~cupcake
