To simplify the expression, we will first find a common denominator for the terms inside the parentheses:

(3/c + 3/c + d) = (6/c + d)
(6/c + d) × c / 18(2c + d)

Now, we can multiply the terms with like terms to simplify the expression further:

(6/c) × c = 6
d × c = cd

Therefore, the simplified expression is:

6/18(2c + cd)
= 2/6(2c + cd)
= (1/3)(2c + cd)
= 2c/3 + cd/3