# Probability after time

1. Jan 22, 2012

### DarkFalz

Hello,

i've been wondering about the following. If only this is information is given:

"each 10 days, the probability that machine A fails is 10%, after which the machine A receives
maintenance"

is it correct to say that each 5 days the probability is 10%/10= 1%?

2. Jan 22, 2012

### mathman

Assuming an exponential model for decay (typical for problems of this nature), the probability for survival after 10 days is .9 (90%), so the probability after 5 days is √.9 ~ .95, so the failure probability would be ~ .05 (5%).