Thank you for the opportunity to help you with your question!
a)A room $56 ..If you rent two additional rooms you add the discounts. The second and the third room would only be given discounts which is $2 each. it would add to $4 . Subtract $4 from $ 56 , the answer is $52.
hence each room is $52.
b) To get the total for the three rooms combined, add $52 + $52 + $52
the answer is $156.
Please let me know if you need any clarification. I'm always happy to answer your questions.