sum of multiples of 2 variables

Perhaps something like this:

Private Sub Worksheet_Change(ByVal Target As Range)

Dim Cell As Range
Dim i As Integer

Set r = Range("F12:F17")
If Intersect(Target, r) Is Nothing Then Exit Sub
Application.EnableEvents = False
  
'' Place solver run macro here

Application.EnableEvents = True
End Sub

This code should placed in the sheet where you have the solver setup. Right click on the sheet tab, click on "View code" and incert code.

Alf