In 2001, a 256 MB USB flash drive cost $ 169. In 2017, a pack of ten 256 MB USB flash drives can be purchased for $ 29. Assuming the value of a flash drive has depreciated linearly with time, write a formula giving the cost of a single 256 MB USB flash drive as a function of the number of years since 2001. For this problem you can assume that you don't get any special discount for purchasing ten instead of one.