Question

Eight different battle tanks fired a round of bomb and continued firing at an interval of 2, 3, 4, 5, 6, 7, 8 and 9 seconds respectively. In 7 hours how many times did they fired together?

Answer 1

First, Calculate the LCM of 2,3,4,5,6,7,8 and 9 which is 7560.
so the first time they all fire together is at 7560 seconds.

Now, 7 Hours = 7×60×60 seconds = 25200 seconds

In 7 Hours, they fire together for 25200/7560=3.33 ≈ 3 Times


so, In 7 Hours , Battle Tanks fire together for 3 times