Let the numbers be 3x, 4x and 5x.Then, their L.C.M. = 60x.So, 60x = 2400 or x = 40. The numbers are (3 x 40), (4 x 40) and (5 x 40).Hence, required H.C.F. = 40.
To solve this question quickly, first remove decimal by multiplying each term with 100,Then terms become 210, 105, 63Then HCF of above terms is 21, So Answer is 0.21