40% of major airline companies equip their planes with wireless internet access. 70% of major airlines offer passengers free on-board snacks. What is the greatest possible percentage of major airline companies that offer both wireless internet and free on-board snacks?	Select the correct option:
A) 30 %
B) 40 %
C) 50 %
D) 60 %
E) 70 %

Rationale: "to maximize the percentage of companies offering both , let ' s assume that all 40 % of companies which offer wireless internet also offer snacks . the answer is b ."
Answer: B