In an industrial area three factories give out sirens at an interval of 40 min, 1 hour anf 1 and a half hour. respectively. Find the time between the two simultaneously sounds of three sirens.

5 answers

6 hrs
Very good
Plzz tell the method solved
In an industrial area ,three factories give out sirens at an interval of 40 minutes , 1 hour and one and a half hour, respectively. Find the time between two simultaneous sounda of three sirens.
Find the LCM of 40 , 60 and 90 then divide the answer by 60

Ans: 6