Question

6 bells commence tolling together and toll at intervals 1 2 3 4 5 and 6 minutes respectively. in 15 hours how many times do they toll together

Answer 1

1 hour = 60 mins
15 hours= 60×15
=900 mins
now,
l.c.m. of 1,2,3,4,5,and 6 is equal to 60
now,
900÷60
=15
Hence the six bells toll together at an interval of 60 mins and in 15 hours they toll 15 times together