Question

Five persons five bullets at the target at an interval of 6, 7, 8, 9 and 12 seconds respectively. the number of times they would fire the bullets together at the target in an hour is

Answer 1

LCM(6, 7, 8, 9, 12) = 504
1hour = 3600 seconds
Number of times they hit together = $\frac{3600}{504}$
                                                          = 7
In 1 hour they hit the target 7 times together.