Find the common factors and the highest common factor of each of the following
a. 6, 8 and 10
b. 4, 8 and 12
c. 10, 15 and 20
d. 6, 12 and 24
e. 8, 12 and 16
f. 13, 26 and 39
h. 16, 32 and 40
g. 12, 14 and 16
i. 16, 56 and 64
j. 8,24 and 40
k. 7, 35 and 42
l. 22,44 and 66