math
posted by fashionista .
local store going out of business. Owner decreases all prices by 5% every day until all items are sold.
Customer wants dress priced at $2500.
How long does she have to wait for repeated discounts to reduce price of dress to less than $700?

Let d be the number of days of required discounts.
2500*(0.95)^d = 700
0.95^d = 0.28
d = log.28/log*.95 = 24.8
That means 25 days to be less than $700.