Complete Question
The complete question is shown on the first uploaded image
Answer:
the value of 
Explanation:
From the question we are told that
The equation is (x + y = 40)
The first value of x is 
The second equation is (0.75x + 1.5y = 40)
So substituting 

=> 
Now substituting y and
into second equation

=> 
So 
Vertebrate is the answer I think.
Explanation:
Take a measuring cylinder and fill it with a certain amount of water. Measure this amount of water.
Place the paper clip in the filled measuring cylinder. You will notice that the water level has gone up. When we place the paper clip in the cylinder the volume of the paper clip gets added to the volume that was present in the cylinder.
The volume of the paper clip will be the final volume of water with the paper clip - The initial volume of water without the paper clip.
Any irregularly shaped object's volume can be determined by this method.
Give me some answer choices and i will be happy to help