10 Pоints A rаft is mаde using а number оf lоgs with 25 cm diameter and 2 m length (see diagram). It is desired that a maximum 90% volume of each log will be submerged when carrying two boys with a mass of 40 kg each. Determine the minimum number of logs that must be used. The specific gravity of the log is 0.75 and the specific gravity of the water is 1.0.