Three number are in the ratio of 3 : 4 : 5 and their L.C.M. is 1800. What is their H.C.F.?
Choose the correct choice from the following choices.
A) 10
B) 20
C) 30
D) 40
E) 50
Let the numbers be 3x, 4x and 5x.   Then, their L.C.M. = 60x   60x = 1800   x = 30   The numbers are (3 x 30), (4 x 30) and (5 x 30).   The H.C.F. is 30.   The answer is 30.
<result>C</result>
Three number are in the ratio of 3 : 4 : 5 and their L.C.M. is 1800. What is their H.C.F.?