Answer:
(3 x 6) + (2 x 12) + (20 x 18)
Explanation:
Number of cartons containing 6 eggs

Number of cartons containing 12 eggs

Number of cartons containing 18 eggs

So,
expression that represents the problem is given by
Number of cartons containing 6 eggs + Number of cartons containing 12 eggs + Number of cartons containing 18 eggs = (3 x 6) + (2 x 12) + (20 x 18)