Question

Each Saturday, a store reduces the price of any unsold

item by 10%. If an item was priced at $80, on Saturday
of the first week it is marked down to $72. At the end of
the second week, it drops to $64.80, and at the end of
the third week the price is decreased to $58.32. If this
continues for 10 weeks, what should be the selling
price for an item that was originally priced at $80?

Answer 1

Answer: $27.89

Explanation:

Since the price decreases every week by 10%, its is basically being marked down to 90% of its original value. We can construct an equation for this, where we have our original value, multiply by a modifier, and raise the modifier to a power equal to the number of weeks it is on sale. Since the original price was $80, that will be 80. Since it is 10% off, we will multiply by 0.9, and since its ten weeks, we will raise the 0.9 to the power of 10.

Thus, 80×0.9^10 = 27.89