In Delhi sixty percent of the signals are switched green at any given point of time. Thirty percent of signals that are supposed to be red are green and ten percent of the signals that are supposed to be green are red. Find what percentage of the signals that are green are supposed to be red? Assume that there are no yellow lights. Don't know the answer !

1) 15%
2) 30%
3) 10%
4) 25%