You've heard of fighting for survival, but have you ever heard of doing math for survival? This fun brain teaser from the folks at TED-Ed wants to know if you have what it takes to help all of your friends escape across this bridge to safety before the zombie horde gets you all. There's just one small problem. Only two people can cross the bridge at once, and you all move at different speeds.
Can you get all your friends across? Lets us know in the comments how long it takes you to solve this tricky puzzle.