Interesting Co-ordinate geometry

Equation of a line, n is given by y = (4x/3) - 100.
What is the smallest distance from (0,0) to any point on the line?

48
50
60
75
100

I am sorry, I still dont get it. I would really appreciate it if someone can explain where we are getting "80 are supposed to be ON"? It doesn't say so anywhere in the question. It says 80 lights are on. And that must be the wrong number because some lights that are supposed to be off are ...

For every 12 rackets factory produces, 11 are acceptable. To get x acceptable rackets, you need to produce 12x/11.
Here x is 1320 so we need to produce 1440 per day to get 1320 good ones. i.e. 60/hr.

Awesome solution! Thanks.