A man was walking along the platform outside a church. It was just six O' clock in the evening . The Church bell started ringing : "DING". The man immediately noticed his watch. It showed 18:00:00. He was looking at his watch. When the sixth bell rang he noticed the time in his watch. It showed 18:00:30 So till the sixth bell rang it has taken 30 seconds. How much time will it take at 12 O' clock to ring the bells ?