Multiplying Two Arrays in Excel VBA

Your have a few issues which I think I've corrected below. One of the things you'll notice about my code is that I use Variant variables to loop through the arrays instead of identifying the element by number (e.g. myArrayElm instead of myArray(x)). This is just my personal preference.

Sub Test1()
Dim x As Long
Dim myArray         'Your first array
Dim myArrayElm      'A variable for the elements in your first array
Dim myArrayAdj      'Your second array
Dim myArrayAdjElm   'A variable for the elements in your second array

'Add values to your arrays
myArray = Array(24800, 26300, 27900)
myArrayAdj = Array(1.0025, 1.005, 1.0075, 1.01)

'Loop through the elements in your first array
For Each myArrayElm In myArray
    'Loop through the elements in your second array
    For Each myArrayAdjElm In myArrayAdj
        x = x + 1
        'Multiply the two array elements together
        Cells(x, 1) = myArrayElm * myArrayAdjElm
    Next myArrayAdjElm
Next myArrayElm

End Sub

This code loops through each element in both arrays, multiplies the two elements, and stores the values in a list beginning in cell A1.

Now, if you have a large dataset you're working with, the below example will be more efficient and will finish quicker since it stores the results in another array and then pastes the results to a sheet all at once instead of individually:

Option Base 1

Sub Test1()
Dim x As Long
Dim myArray         'Your first array
Dim myArrayElm      'A variable for the elements in your first array
Dim myArrayAdj      'Your second array
Dim myArrayAdjElm   'A variable for the elements in your second array
Dim Results         'An array for your results
Dim r As Range      'Range to store values

'Add values to your arrays
myArray = Array(24800, 26300, 27900)
myArrayAdj = Array(1.0025, 1.005, 1.0075, 1.01)

'Set the size of the results array
ReDim Results(1 To UBound(myArray) * UBound(myArrayAdj))

'Loop through the elements in your first array
For Each myArrayElm In myArray
    'Loop through the elements in your second array
    For Each myArrayAdjElm In myArrayAdj
        x = x + 1
        'Multiply the two array elements together
        Results(x) = myArrayElm * myArrayAdjElm
    Next myArrayAdjElm
Next myArrayElm

'Set the destination range
Set r = Range("A1:A" & UBound(Results))

'Paste results to sheet
r = Application.Transpose(Results)

End Sub

Note the Option Base 1 at the top. This just means that all the arrays will now start at element 1 instead of element 0 which is the default.