Eighty percent of the lights at Hotel California are on at 8 p.m. a certain evening. However, forty percent of the lights that are supposed to be off are actually on and ten percent of the lights that are supposed to be on are actually off. What percent of the lights that are on are supposed to be off?
I'm doing something wrong on this one. who can help?
80/100 lights are on at HC. .4(80) = 32 lights should be off.
20/100 lights are off at HC. .1(20) 2 lights should be on
32 should be off/80 are on = 40%