October 21, 2011

It’s not often that we have British actor Jude Law ( above) explaining maths to us, but in the new Hollywood film CONTAGION

he demonstrates how quickly a deadly virus could spread … (1.17 point on trailer)



Jude Law plays the colourful blogger Alan Krumwiede. Gwyneth Paltrow’s character dies and Matt Damon tries to save his daughter. (See pics)









Krumwiede says ‘ On day one there were 2 people, then 4, then 16 … in three months it’s a billion. That’s where we’re heading.’ Is he right?



.Now this bug is highly contagious, but Krumweide’s estimates start high and end low. In the film he says the number of infected people will grow according to the series 2, 4, 16, 256 and then a number Mathspig,um, missed. (I was munching popcorn.)

This is wrong. According to this progression by Day 3 each person must go out an infect 16 other people. By Day 4 they must infect 256 people each. By Day 5 they must infect 65,536 people each. That is a BIG cough.

Then he claims that in 3 months or 90 days 1 billion people will be infected. That’s so sweet. If the Gweny bug was so highly  contagious the human race wouldn’t last that long. Oddly, however, this number has synergy with the TWILIGHT VAMPIRES.

Even if each germ-riddled person infected only 1 other healthy person each day, this is how long we would last:

You may need to use the WEB 2.0 calculator to solve this problem.




Not everyone on earth would die, of course. As the numbers drop so do the infection rates. Meanwhile, some people in remote areas would not get infected and some people would have immunity and that’s when the plot gets hot, HOT, HOT!!


  1. […] calculations were updated for clarity on 21 OCT 2011 after I’d worked on my JUDE LAW CAN’T DO MATHS post. Now in the Twilight Series it takes 3 days for a  human to turn into a vampire. So we will […]

  2. Nice post! Another place where Hollywood gets exponentials wrong is in the classic Star Trek episode “Court Martial.” Kirk is explaining how a booster device will increase the computers ability to hear sounds on the ship and explains that the device will “increase that capability on the order of one to the fourth power”…hmmm!

    • Great to hear from you Girlsangle girls. I’ll be watching your website. Cheers Mathspig

  3. One problem with this, how on earth did everyone miss the fact that earlier in the film we are told the R0 is the number of people an infected person will infect. There isnt even a mention of “per day”, so how did they even reach a power series to begin with?

    And why are we starting with two people infected? That is not what an R0 of 2 specifies at all, there could easily be a single patient 0, and indeed it appears plausable that Gwyneth Paltrow provided that cross-over into the human population. Perhaps I am being too harsh and he is referring to “new infectees”, but in that case the numbers are even more ridiculous!

    I cant understand how this film got such positive reviews for “scientific content”, even the way they attempted to “contain” the infected man on the bus was entirely negligent, it makes my brain bleed.

    • Dear Bleeding Brain, Thanks for the comment. And I agree. The maths and science were iffy, at best. Cheers Mathspig

  4. Used this in math class today! Great post.

    • Woo Hoo! That’s great news, Kristina! I’ve linked your blog to Mathspig. Thanks for letting me know. Cheers Excited Mathspig.

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