Answer:
17) see explanation
18) 3850 ft^2
Explanation:
17) not sure where area is being shaded. so i can't help you with that one. if you could clarify i could edit this or send a separate answer for it
18) find the area of the two rooms. both have a 50x40 room so the total area is 4000 ft^2. But, there is an overlap so you need to subtract the aquarium once. the area of the aquarium is 30*5 = 150 ft^2. Subtract 4000ft^2 by 150 ft^2 and you get 3850 ft^2