Question

five bells start ringing together. if the bells ring at intervals of 2,4,6,8 and 10 seconds respectively, after what interval of time will they ring together again?
​

Answer 1

L.C.M. of 6, 5, 7, 10 and 12 is 420. So, the bells will toll together after every 420 seconds i.e. 7 minutes.