hello349
contestada

URGENT HELP PLEASE
at 10am three bells ring together. The large bell rings every four minutes, the old bell rings every 7 minutes and the small bell rings every three minutes. When will be the next time that all the three bells ring together?

Respuesta :

Old bell: once every 7 minutes
Small bell: once every 3 minutes.
Large bell: 4 minutes

The first time they will ring together is at the lowest common multiple of 7,3 and 4. 
Large bell = 4 mins
Old bell = 7 mins
Small bell = 3 mins

LCM = 4 x 7 x 3 = 84

It will ring together again after 84 mins.

84 mins after 10am = 11:24

-----------------------------------------------
Answer: 11:24
-----------------------------------------------