Question

Four alarm watches ring in the interval 3,5,7,and14 sec . If they rang at 4' clock in the morning then when they will ring together

Answer 1

LCM of 3, 5, 7, 14 is 3*5*7*2 = 210 sec

So they will ring after every 210 sec together

or after 3 min 30 sec

As they rang at 4 : 00 AM

so next they will rang at 4 : 03 : 30 AM