Array 運用

Question 1：Find out the total Qty of model "AA"

{=SUM(($B$4:$B$8="AA")*$C$4:$C$8*$D$4:$D$8)}

Calculation process:

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Question 2：Find out how many model in the list.

{=SUM(1/COUNTIF($B$8:$B$21,$B$8:$B$21))}

Remarks:
根據相同型號出現的次數，計算所佔的比例，而相同型號的總和為1！