I am a woodworker, and am designing a two part magnetic/spring lock for my blanket chest. The first part has 3 master buttons (primary buttons A, B, C), and the second part has 11 secondary buttons (1, 2, 3, ....11). What you do first is choose 1 of the 3 master buttons that opens the first part of the lock. Then out of the secondary buttons, you choose 3 out of the 11 that will open the rest of the lock (and can be pressed in any particular order). So, not only do you have to choose the correct master button, but 3 secondary buttons as well. The master control that you choose stays depressed because of a lever, but each secondary button is spring-loaded so it pushes back out when you release it. The interior of the lock (the guts) is made up of springs, neodymium magnets, steel rods, and blocks of wood (Which really should not matter because it has nothing to do with the math problem). So essentially you are choose 1 out of 3 and 3 out of 11 at the same time. So my question is how do i figure out how many differentpossibilities are there in this lock? for example, A, 1, 2, 3 or C, 4, 9, 11.(adsbygoogle = window.adsbygoogle || []).push({});

Is there an equation for this problem, or do I have to sit down and figure it out the long way?

**Physics Forums - The Fusion of Science and Community**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Two-part problem; calculating possibilities of lock

Loading...

Similar Threads for part problem calculating | Date |
---|---|

Calculus by Spivak, Chapter 2, Problem 6, Part 3 | Jul 24, 2015 |

Integration by parts problem involving vector functions | Aug 9, 2013 |

Problem with the expansion of integration by parts | May 15, 2013 |

Problem with Integrating by parts | Jul 23, 2012 |

How do you know when to use integration by parts on a problem? | Sep 23, 2009 |

**Physics Forums - The Fusion of Science and Community**