Respuesta :

24: 1,2,3,4,6,8,12,24
30: 1,2,3,5,6,10,15,30
42: 1,2,3,6,7,14,21,42

The common Number is 6 for all three, so the answer is "6".
24=2*2*2*3
30=2*3*5
42=2*3*7

the common group is 2*3 wiich is 6


6 is GCF