DS: Averages Question

[DCJ]

Can someone explain?

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%

Ans: C

[praky_rules]

New Average = Old Average + (10% increase in the top 5 priced items + 10% decrease in the bottom 5 priced items)/10.

10% of the top 5 items will be greater than 10% of the bottom 5.

So New Average will be higher than the old average

C.

Two things worth noting are $ 165 is irrelevant and price cannot be negative!(If the numbers were positive and negative, this conclusion is not possible)