Hopefully your math skills are sharp enough for the doubling virus puzzle. Imagine there is a virus that doubles every single day. On the 67th day of doubling, the virus has reached its maximum population. On what day did the virus reached half of its maximum population? How did you figure it out?

So on what day did the virus reached half of its maximum population?

The correct answer is :

So on what day did the virus reached half of its maximum population?

The correct answer is :

**"At the end of the 66th day"****Since the virus doubled the 67th day for the last time this means that his half of maximum population was reached at the end of the 66th day. So for example if the population at the end of the 66th day doubles from 1000 x 2 (double) = 2000 the 67th day it doubled for the last time to 2000 x 2 = 4000 (max population) which means that in any case the number of the population at the 66th day is equal to the half of the maximum population.**