What is the simplification of 6ab over 3b?

6ab / 3b = 2a

so

b / b cancels each other out

6 / 3 = 2 / 1

Example: a = 4 and b = 5

6ab = 6 x 4 x 5 = 120

3b = 3 x 5 = 15

120 / 15 = 24 / 3 = 8 = 2a = 2 x 4