Summarize with an weighted average

[hendricksk]

I need help with producing a weighted average when only some of the lines will get summarized. If I summarize, then how can I also get Apples to calculate a weighted average?

Product   Weight  Qty

Apples     1           3

Lemons    2           5

Cherries    2          4

Apples       3           5

[binu_acs]

@hendricksk one way of doing this

[Qiu]

@hendricksk 
How do you want to calculate the weighted average?
Can you give a bit more details?