Seven guns all commence firing together at a target but they continue to fire at interval 2,3,5,7 and 12 minutes. After how many hours do all five guns fire at the same time as they did in the beginning?

Question

Thanks for helping

Answer 1

The least common multiple is 420.

420 / 60 = 7 hours

Answer 2

The LCM of 2, 3, 5, 7, and 12 is 420

So they will all fire together again 420 minutes, or 7 hours from now