Question

a bell tolls every 10 minutes. another bell tolls every 15 minutes. both bells toll at 6:00pm. they will toll together at what time

Answer 1

basically, we need to find the lowest common multiple of 10 and 15.

that multiply would be 30. That means that the bells will ring together in 30 minutes.
So 30 minutes from 6 p.m. is 6:30 p.m. <==

Answer 2

The answer is 6:30 pm