An integer is assigned to each vertex of a tetrahedron. The value of an edge is defined to be the sum of the values of the two vertices it touches, and the value of a face is defined to be the sum of the values of the three edges surrounding it. The value of the tetrahedron is defined as the sum of the values of its four faces. Suppose the sum of the integers assigned to the vertices is . What is the value of the tetrahedron?
30
45
60
90
120
