An alternate approach is treat this as a WEIGHTED AVERAGE problem.dddanny2006 wrote: I buy 100 pens from a dealer for $20 a piece
I sell 80 of those pens for $30 a piece,since the other 20 dont get sold I return them back to the manufacturer for a 50% refund thats $10
Now if Im asked to find the profit]
The purchase price per pen = $20.
Of 100 pens:
80 are sold for $30 each, implying a profit of 50% per pen.
20 are returned for $10 each, implying a loss of 50% per pen.
Average profit/loss percentage per 100 pens = (80*50 - 20*50)/100 = 30%.
Since each of the $20 pens earns an average profit of 30% -- $6 -- the total amount of profit for the 100 pens = 100*6 = $600.
For an official problem that can be solved VERY quickly with this approach, check here:
https://www.beatthegmat.com/official-gui ... 55918.html
