Question

Three bells toll at intervels of 14, 21 and 42 minutes respectively. If they toll together at 11:24 am., when will they toll together for the first time after that ?

Answer 1

three bells toll together at intervals of 14mins,21mins and 42 mins

they toll together at 11:24am

now when they will toll together

we find LCM

14=2×7

21=3×7

42=2×2×2×3

LCM=2×7×3×4

LCM =168

after 168 minutes or 2 hours 48 minutes the bells will toll together again

means at 3:12pm