A family is having 5 members of different age group.They want to cross a bridge in night.They are having one candle which is necessary for any crossing in the bridge.One person of the family can cross the bridge in 1s, another in 3s, and the rest in 6s, 8s and 12s respectively. Maximum no.of persons allowed on the bridge is 2 at any time.While crossing the bridge as a group of 2 persons, the fast moving member will move with the speed of slow moving member only. How they can cross the bridge in less than 30s?
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