Three number are in the ratio of 3 : 4 : 5 and their L.C.M. is 900. What is their H.C.F.?
Choices:
A) 5
B) 15
C) 25
D) 35
E) 45
Let the numbers be 3x, 4x and 5x.   Then, their L.C.M. = 60x   60x = 900   x = 15   The numbers are (3 x 15), (4 x 15) and (5 x 15).   The H.C.F. is 15.   The answer is 15.
<result>B</result>
Three number are in the ratio of 3 : 4 : 5 and their L.C.M. is 900. What is their H.C.F.?