Follow these steps to calculate the weighted average:
1– Type =SUMPRODUCT in cell B12, select the cell range B5:B9 against array1 argument and C5:C9 against [array2] argument of the function.
How the formula works
The formula (=SUMPRODUCT(B5:B9*C5:C9)/SUM(C5:C9)) used has combination of two functions:
- the SUMPRODUCT function multiples arrays together and sums the result, and,
- the SUM function calculates the sum of all weight.