Here, we need to take the L.C.M. of 2,3,4,5 and 6 to find out the number of days after which all these 5 groups meet on the same day. So, L.C.M. (2,3,4,5,6)=60 We can say that the 5 groups meet on the same day on every 60th day. ∴ Number of times all the 5 groups meet onthe same day within 180 days =