# Math Help - inflation rate

1. ## inflation rate

If the inflation rate is 100j% per annum over a period of n years, what is the purchasing power of a dollar at the end of n years as a percentage of its purchasing power at the beginniing of that period. this is what I did:

The purchasing power of a dollar at the end of n years of 100% annual inflation is $1.100^-n or 1 and I know this must be set up inncorrectly. The dollar should be less but I don't think this is the right answer. Thankx, Keith 2. Hello, Keith! If the inflation rate is 100% per annum over a period of n years, what is the purchasing power of a dollar at the end of n years as a percentage of its purchasing power at the beginning of that period? I worked out the math behind this problem, . . but here's a baby-talk explanation. If the inflation is 100% per year, . . then an item costing$1 this year will cost $2 next year, . . and$4 the next year, then $8 the next year . . . In other words, the purchasing power is cut in half every year . . . . . to ½ the first year, to ¼ the second year, etc. At the end of the nth year,$1 will be worth only 1/(2^n) dollars.

As a percentage, the purchasing power is 100/(2^n) percent.