Uploaded May 2016 | Updated September 2026, 1 day ago

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This simple brain teaser is not so easy. A virus is doubling every singe day. On the 67th day the virus has reached its max population. When will the virus reach half of its max population.

My name is Chris and my passion is to teach math. Learning should never be a struggle which is why I make all my videos as simple and fun as possible. I cover all subjects from basic level math through upper level calculus and statistics. I also make brain teaser and Rubik's cube videos for fun.

Check out all of my other brain teasers.

The Easiest brain teaser driving the internet insane (Fruit problem)
youtube.com/watch?v=yuseE8o_UK8

Heaven and hell - Brain Teaser
youtube.com/watch?v=YOgKI0HWCnA

Two Burning Ropes - Brain Teaser
youtube.com/watch?v=IyGV5Ry9pQw

Cross the river - Brain Teaser
youtube.com/watch?v=vTWfsUZSCXo

Game show - Brain Teaser
youtube.com/watch?v=ruX49qla1Ig

Don't checkmate - Brain Teaser
youtube.com/watch?v=fuEjP3XfaXA

Counterfeit coins - Brain Teaser
youtube.com/watch?v=d6eF98_4lHU


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