In excel, how do you multiply and sum alternating cells in a row?
Solution 1:
Assuming the last cell in the range is H1:
=SUMPRODUCT(A1:F1,C1:H1,N(ISODD(EVEN(COLUMN(A1:F1)-MIN(COLUMN(A1:F1))+1)/2)))
Or, for Office 365:
=SUMPRODUCT(A1:F1,C1:H1,N(ISODD(EVEN(SEQUENCE(,COLUMNS(A1:F1)))/2)))
Note the deliberately offset ranges (A1:F1 and C1:H1).