Problems on H.C.F and L.C.M
Five bells ring together and ring at intervals of 2, 6, 8, 12 and 15 seconds respectively. How many times will they ring together in 60 minutes?
L.C.M. of 5, 6, 7, 8 = 840.Required number is of the form 840k + 3Least value of k for which (840k + 3) is divisible by 9 is k = 2.Required number = (840 x 2 + 3) = 1683.