求各位大神，已知平均数，求生成几个随机数！

Option Explicit
Const NUM As Long = 100
Sub abc()
　Dim i, j, sum
　ReDim a(1 To NUM, 1 To 3)
　For i = 1 To UBound(a)
　　For j = 1 To 2
　　　a(i, j) = Int(Rnd * 16) + 15
　　　sum = sum + a(i, j)
　　Next
　　If 27 * 3 - sum >= 15 And 27 * 3 - sum <= 30 Then
　　　a(i, j) = 27 * 3 - sum
　　Else
　　　i = i - 1
　　End If
　　sum = 0
　Next
　[a1].Resize(NUM, 3) = a
End Sub

A2（A1留空）=RANDBETWEEN(MAX(0,36-SUM(A$1:A1)+(ROW()-2)*15-(4-ROW())*15),MIN(15,36-SUM(A$1:A1)+(ROW()-2)*15))+15 下拉3行

在要求的范围内完全随机。