3,5,7 are coprime, the least common multiple =3*5*7= 105.

Number of people = 105+2= 107 (person) 2,2 This question is hard to say. I am a student, too. Ask the teacher to teach you that 3,30 kilograms of oil is x kilograms, and x-( 1/3 x+4/5 x)= 4, and then you can't figure it out yourself.