Question

four bells toll at intervals of 4, 7, 12 and 84 seconds. The bells toll together at 5 o'clock. when will they again toll together​

Answer 1

All the bells toll together at (LCM) of the timings given

LCM of 4, 7, 12 and 84 is =>

4 = 2², 7 = 7¹, 12 = 2² × 3¹ and 84 = 2² × 3¹ × 7¹

LCM = product of highest power of all the factors

therefore LCM of all the above four numbers =>

2² × 7¹ × 3¹ => 84

this means all the four bells toll together every 84 minutes => 1 hr 24 min

therefore four bells will toll together at 5 + 1h 24m

=> 6:24