I am looking for a formula that would sum duplicate items (A1,A5=xxxx1) linked to the drop down month box on cell C, the result would be 15, if the month is the drop down box "D", the result would be 5.
A B C D
1 xxxx1 1 1
2 xxxx1 2 1
3 xxxx1 3 1
4 xxxx1 4...