Ten different items are for sale in a store, and each is sold at a different price. The average (arithmetic mean) price of these 10 items is $165. If the prices of all the items are changed, will the average price increase? (1) The five most expensive items each increased in price by 10%. (2) The five least expensive items each decreased in price by 10%. OA : C I took 4 minutes for this! any suggestions..

Stmt I No idea on what happenned to the 5 least expensive items. They could have given away for free or could have increased/decreased. ISNUFF Stmt II No idea on what happenned to the 5 most expensive items I would pick 10 numbers which are multiples of 10 10 20 30 40 50 60 70 80 90 100 As u can see a increase by 10% to the larger elements(>=50) of the list keeps getting more and more whereas a decrease on the smaller elements(<=50) keeps getting less and less. So overall sum/total increase and the no of elements remains the same and hence the average will definitely increase. Choose C Some useful concepts on averages: If a constant k is added to each of the elements in a list then the new average = old average + k. If a constant k is subtracted to each of the elements in a list then the new average = old average - k. If each element is multiplied by a constant k then the new average = old average * k If each element is divided by a constant k then the new average = old average / k I just included these concepts as an FYI for this problem the 10% increase and decrease will not be a constant as explained in my post above. Hope this helps and I have not misstated something! Experts please correct me if so. Regards, CR