Pipes A and B are filling pipes whereas pipe C is an emptying pipe. Pipes A and B together can fill a tank in 30 hours. A, B and C together takes 33\( {1\over 3}\)% more time than what A and B together take to fill the tank. How much time (in hours) will C alone take to empty the full tank?
1
150
2
100
3
90
4
120