Question

four persons fire bullets to hit a target at an interval of 7 8 9 and 12 seconds respectively. how many number of times they would fire the bullets together to hit a target in an hour?

Answer 1

7,8,9,12

7 = 7

8 = 2x2x2

9 = 3x3

12 = 2x2x3

LCM = 7x2x2x2x3x3 = 504 seconds

after every 504 seconds they will hit target together

1 hour = 60 mins = 3600 seconds

so total number of times they hit target together in 1 hour = 3600/504 = 7