Basic SUM or SUMPRODUCT question

[zutalors212]

I have data in columns a, column b, and column c.

1. i'd like to multiply columns a and b, and then sum all of this up.

2. i'd like to sum up the column c.
3. i'd like to divide 1 by 2.

i tried with "= SUM (a1:a100*b1*b100)/SUM(c1:c100), but it's not
correct.

suggestions?

 

[Mark Lincoln]

Try

=SUMPRODUCT(A1:A100,B1:B100)/SUM(C1:C100)

Not tested, but should work.

 

[Bob Phillips]

=SUMPRODUCT(A1:A4,B1:B4/C1:C4)

--

HTH

Bob Phillips

(remove nothere from the email address if mailing direct)

 

[Mark Lincoln]

zutalors,

Bob's formula multiplies the first array by the result of the second
array divided by the third array. If I'm not mistaken, you want the
sum of the first array multiplied by the second, and that result
divided by the sum of the third array.

Bob's example provides a different result from mine. You'll need to
calculate the desired result by hand to determine which formula does
what you need.

 

[zutalors212]

You were right.

 

[zutalors212]

Thanks my friend.