Below is a possible solution to the challenge Challenge 41 – Sum the Maximum Number where duplicates Exist
Enter the below formula as Array Formula i.e. not by pressing ENTER after entering your formula but by pressing CTRL+SHIFT+ENTER. If you are copying and pasting this formula, take F2 after pasting and CTRL+SHIFT+ENTER. This will put { } brackets around the formula which you can see in Formula Bar. If you edit again, you will have to do CTRL+SHIFT+ENTER again. Don't put { } manually.
=SUM((MATCH(A2:A10,IF(COUNTIFS(A2:A10,A2:A10,B2:B10,">"&B2:B10)=0,
A2:A10),0)=ROW(A2:A10)-MIN(ROW(A2:A10))+1)*B2:B10)
The workbook illustrating the above solution can be downloaded from Solution – Challenge 41 – Sum the Maximum Number where duplicates Exist