Three number are in the ratio of 3 : 4 : 5 and their L.C.M. is 2400. Their H.C.F. is:  Choose the correct choice from the following choices.
A) 10  B) 50  C) 40  D) 20  E) 30
Let the numbers be 3x, 4x and 5x.   Then, their L.C.M. = 60x.   So, 60x = 2400 or x = 40.   {\color{Blue} \therefore } The numbers are (3 x 40), (4 x 40) and (5 x 40).   Hence, required H.C.F. = 40.   Answer: Option 40
<result>C</result>
Three number are in the ratio of 3 : 4 : 5 and their L.C.M. is 2400. Their H.C.F. is: