There is a virus codenamed Covid-Pi spreading across the world. It is highly contagious and causes high mortality rates. In order to decide the quarantine period for people who are at risk having Covid-Pi virus, the Taskforce must know the incubation period of the virus, i.e., how long it causes a person to show symptom after he has contacted the virus. Worldwide Statistics shows that the incubation periods follow a Normal Distribution with a mean of 12 days and a standard deviation of 5 days.

Find the incubation period that only 3% of the Covid-Pi virus will last beyond before showing symptom in human bodies.