Sumifs? can this be done with a ranged criteria?

[plasteredric]

I'm trying to get the average value from a range, i've attached a sheet to better explain what i'm trying to achieve

i've tried the formula "=SUM(B15*B13,C15*C13,D15*D13,E15*E13)/F13", which works to get the answer I want but it seems a bit messy.

cheers

[offthelip]

try:

=SUMPRODUCT(B13:E13,B15:E15)/F13