sarahenry Posted October 15, 2011 Share Posted October 15, 2011 Hi, An event A happens very 13 years Another event happens every 17 years. How to calculate when they happen together again Thanks in Advance Sara Link to comment Share on other sites More sharing options...
mooeypoo Posted October 16, 2011 Share Posted October 16, 2011 Is this a riddle or a homework question (IE, should we 'guess the answer', or explain how to try and solve it?) Link to comment Share on other sites More sharing options...
raj bhramar Posted March 12, 2012 Share Posted March 12, 2012 Say event 'A' happens after 13a years and event 'B' happens same day after 17b years. Obviously 17b must be equal to 13a, which is possible only when a = 17 and b = 13. So after 13 * 17 = 221 years Both event happens together again. Link to comment Share on other sites More sharing options...
imatfaal Posted March 12, 2012 Share Posted March 12, 2012 And the Cicadas start to fill the evening air with their song! Link to comment Share on other sites More sharing options...
BJwojnowski Posted March 22, 2012 Share Posted March 22, 2012 they will not occur again in the same material plane. When event A happens 13 years later event B will occur four years after that. event A will occur again twenty six years from the origen and B will occur again in thirtyfour years. If time is linear the difference between the reoccurences will only get larger and larger of course assuming that there is only one frame of reference and the same clock timing both events. -1 Link to comment Share on other sites More sharing options...
raj bhramar Posted March 22, 2012 Share Posted March 22, 2012 they will not occur again in the same material plane. When event A happens 13 years later event B will occur four years after that. event A will occur again twenty six years from the origen and B will occur again in thirtyfour years. If time is linear the difference between the reoccurences will only get larger and larger of course assuming that there is only one frame of reference and the same clock timing both events. OP does not say that event B will occur 4 years after event A takes place. Event A occur every 13 years and event B every 17 years. So if today both events occured together, then counting from today, second occurrence of A will be after 13 years from now and that of B will be 17 years from now. Then third occurence of A will be 26 years from now and that of B will be 34 years from now. Thus the difference goes on increasing for every successive occurrence. Link to comment Share on other sites More sharing options...
CaptainPanic Posted March 22, 2012 Share Posted March 22, 2012 Both events occur in the same year after 221 years. For event A, which occurs every 13 years, that will be the 17th time it occurs since we started counting. For event B, which occurs every 17 years, that will be the 13th time it occurs since we started counting. Link to comment Share on other sites More sharing options...
ewmon Posted March 22, 2012 Share Posted March 22, 2012 Sarahenry, these two numbers (13 and 17) are also primes, and so finding the answer mathematically is easier than if they weren't primes. This problem sounds like homework, when leads me to expect that you'll encounter similar but more complicated problems next. For example, Event A recurs every 6 years and Event B recurs every 8 years, or Event A recurs every 3 years and Event B recurs every 9 years. These problems involve finding and using common factors. Link to comment Share on other sites More sharing options...
BJwojnowski Posted March 23, 2012 Share Posted March 23, 2012 Thank you for clearly stating what I was trying to say. Link to comment Share on other sites More sharing options...
John Cuthber Posted March 23, 2012 Share Posted March 23, 2012 There is a whole stack of related stuff here http://en.wikipedia.org/wiki/Least_common_multiple Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now