Question

Four bells toll after an interval of 16,45,60,75 seconds respectively.these bells begin to toll together at 9a.m. at what time will they next toll together

Answer 1

Take L.C.M of 16, 45, 60, 75.
factors: 2*2*2*2*3*3*5*5
L.C.M= 3600

in seconds= 3600
in minutes= 60
in hour = 1

so add:
9+1= 10
so, they beep together again at 10 a.m..