Three children, each of weight 36 kg, make a log raft by lashing together logs of diameter 0.3 m and length 1.8 m. How many logs will be needed to

Three children, each of weight 36 kg, make a log raft by lashing together logs of diameter 0.3 m and length 1.8 m. How many logs will be needed to keep them afloat? Consider the density of wood to be 842 kg/m3. Density of water = 1 x 103 kg/m3