Please help this family to cross to the other side of the bridge.

• "fire":"na"
• "jump":"na"
• "movement":"na"

Notice that: It is night . There is 1 lamp . A maximum of 2 persons can cross at one time, and they must have the lamp with them. Each person walks at a different speed: 1sec 3sec 6sec 8sec 12sec. A pair must walk together at the rate of the slower person. The lamp enough for 30 sec only!!!