Answer
24
Work Step by Step
3,8,4
Find multiple of 3 = 3,6,9,12,15,18,21,24,27....
Find multiple of 8 = 8,16,24,32,40....
Find multiple of 4 = 4,8,12,16,20,24,28....
24 is the smallest number found in all the lists. So 24 is the least common multiple of 3,8 and 4