Astore is selling sculptures. the first week, it prices 6 sculptures at $80 each. after each week, if a sculpture is not sold, it will be priced to sell for 0.85 times the previous week's price. the store needs to sell 6 sculptures for a total of at least $270 to make a profit. what is the last week in which all 6 sculptures could be sold so that the store makes a profit?

80 * 6 = 480 which is the total price for all of the 6 sculptures together if they were bought. You have to mulitply .85 to 480 because it represents how many weeks the price has gone down. 
.480 * .85 = 408 
You then mulitiply 40 with .85 because that's new weeks price. 
408 * .85 = 346.8
You keep doing that until you get to, are are close to $270 
346.8 * .85 = 294.78
294.78 * .85 = 250.56
So your answer would be the 3rd week