Excel dynamic range to calculate percentages

Question

I have three columns in my table date, day and quantity. I want to be able to calculate the quantity percentages by day.

Date | DAY | QUANTITY
 1   | MON |    3
 2   | TUE |    6
 3   | WED |    3
 4   | THU |    1
....
 8   | MON |    3
 9   | TUE |    1

I'm sure there has to be an easier way than hard coding it.

For example I want a formula to calculate total quant on monday over the total which would be 3 + 3 /17 for the values listed and display it in its own cell.

Do i need to use vba or can i just write a formula?

Answer 1

将星期一数量的总和除以总和的公式：

=SUMIF(B:B,"MON",C:C)/SUM(C:C)