2 inflation rate/maths questions.

[chili1]

Hi,

We're having quite a debate here in work.
2 questions.

1.If inflation is set at 5%, how long does it take a sum of money to half in value.
2. If inflation for 5 years is
-5%,5%,5%,10%,10%. If you move the -5% to the last year, has the rate of inflation increased,decreased or stayed the same over the period?

[SplatSpeed]

1.05 to the power x

keep increasing x till you get to 2

[fido]

according to my spready:-

1. 14.2yrs (assuming 0% interest rate)
2. average of 4.85% (annual inflation - assuming 0% interest rate)

.. of course it's ridiculous to assume 0% interest rate