Let number of nodes with exactly two children be x, and with exactly one children be y.
Total degree = 50 + 3x+ 2y −1 (As all nodes with 2 children have degree 3 except the root)
N = Total No. of nodes=x+y+50 --------eq.1
we know 2*total edges = sum of all degree
2(x+y+50-1) = 50 + 3x + 2y -1
2x + 2y + 100 - 2 = 50 + 3x + 2y -1
x = 49 Putting this in eq.1, we get
N = 49 + y + 50
so, y = the number of nodes in T that have exactly ONE children = N - 99